CN102819996B

CN102819996B - Image element circuit, display device, electronic installation and pixel circuit drive method

Info

Publication number: CN102819996B
Application number: CN201210179273.8A
Authority: CN
Inventors: 三并彻雄; 内野胜秀
Original assignee: Joled Inc
Current assignee: Japan Display Design And Development Contract Society
Priority date: 2011-06-08
Filing date: 2012-06-01
Publication date: 2016-12-14
Anticipated expiration: 2032-06-01
Also published as: JP2012255875A; CN102819996A; JP5842263B2; US20120313923A1; US8917264B2

Abstract

The open a kind of image element circuit of the present invention, including: light-emitting component；Storage capacitor；Write transistor, writes described storage capacitor for would correspond to the driving voltage of video signal；And driving transistor, for based on the driving voltage writing described storage capacitor, drive described light-emitting component, in the way of wherein can associating to write the process operation of described storage capacitor with the driving voltage that would correspond to described video signal, control the characteristic of described write transistor.

Description

Image element circuit, display device, electronic installation and pixel circuit drive method

Technical field

The disclosedest technology relates to image element circuit, display device, electronic installation and pixel electricity Road driving method.

Background technology

Now, there is the display device of image element circuit (also referred to as pixel) and include the electricity of display device Sub-device is widely used, and this image element circuit includes display element (also referred to as electrooptic cell).Exist and use Electrooptic cell is as the display device of the display element of pixel, and the brightness of this electrooptic cell is according to being applied to electricity The voltage of optical element or changed by the electric current of electrooptic cell.Such as, liquid crystal display cells is basis The voltage that is applied on electrooptic cell and change the exemplary of the electrooptic cell of brightness, and organic electroluminescence Luminous (described herein after for organic EL) element (Organic Light Emitting Diode (OLED)) is according to by electricity The electric current of optical element and change the exemplary of the electrooptic cell of brightness.Use organic EL element below Organic EL display be to use self-luminous electrooptic cell as the so-called transmitting of the display element of pixel Display device.

The display device using display element can use the matrix system of simply (passive) and active square Array 1 system is as the drive system of display device.But, when having simple structure, passive matrix Display device such as relatively greatly and has difficulties in fine definition display device in realization.

Therefore, active matrix system the most (be see for example Japan Patent by positive exploitation No.4240059 and Japan Patent No.4240068), active matrix system is by using similar being arranged on Active component in pixel controls the picture element signal of the display element being applied in pixel, and this active component is Such as transistor, such as isolated-gate field effect transistor (IGFET) (typically thin film transistor (TFT) (TFT)) etc. are made For switching transistor.

Summary of the invention

However it has been found that when use has the field-effect transistor of back-gate effect (back gate effect) Write for signal and time video signal has high level (that is, to be obtained high brightness), " luminance shortage Phenomenon " occur, the most actually may not obtain the brightness of the incoming level corresponding to video signal.

It is therefore desirable to provide make it possible to obtain more reliably incoming level bright that would correspond to video signal The technology of degree.

According to the image element circuit of first embodiment of the present disclosure, including: light-emitting component；Storage capacitor； Write transistor, writes described storage capacitor for would correspond to the driving voltage of video signal；And drive Dynamic transistor, is used for, based on the driving voltage writing described storage capacitor, driving described light-emitting component, Wherein can be to write the process of described storage capacitor with the driving voltage that would correspond to described video signal The mode of operation association, controls the characteristic of described write transistor.

The display device of basic second embodiment of the present disclosure includes: multiple image element circuits, described pixel electricity Road include light-emitting component, store capacitor, the driving voltage that would correspond to video signal writes described storage The write transistor of capacitor and described for driving based on the driving voltage writing described storage capacitor The driving transistor of light-emitting component, described image element circuit is arranged；And Characteristics Control part, its structure For to write the process operation pass of described storage capacitor with the driving voltage that would correspond to described video signal The mode of connection, controls the characteristic of described write transistor.

Display device according to third embodiment of the present disclosure includes: multiple image element circuits；Multiple holding wires； And multiple scan line, wherein said image element circuit includes light-emitting component, storage capacitor, write transistor And driving transistor, according to the control signal from scan line, described write transistor is arranged on conducting shape In state, and the video signal from holding wire is applied to described storage capacitor by described write transistor； Described storage capacitor keeps the driving voltage of the video signal corresponding to being applied；Electricity is driven based on described Pressure, drive described driving transistor, in order to be fed through the electric current of described light-emitting component, described in write crystal Pipe includes backgate terminal and gate terminal, and connects electric capacity between described backgate terminal and described gate terminal Element and resistive element.

Electronic installation according to fourth embodiment of the present disclosure includes: multiple image element circuits, described pixel electricity Road includes light-emitting component, storage capacitor, writes described for would correspond to the driving voltage of video signal Store the write transistor of capacitor and for driving based on the driving voltage writing described storage capacitor The driving transistor of described light-emitting component, described image element circuit is arranged；Signal generator divides, and is used for producing The raw video signal being applied to described write transistor；And Characteristics Control part, be configured to with by corresponding Driving voltage in described video signal writes the mode processing operation association of described storage capacitor, control Make the characteristic of described write transistor.

Pixel circuit drive method according to fifth embodiment of the present disclosure is a kind of side driving image element circuit Method, described image element circuit includes writing storage capacitor for the driving voltage that would correspond to video signal Write transistor and for driving the driving transistor of display part, described driving method includes: with will Driving voltage corresponding to described video signal writes the side processing operation association of described storage capacitor Formula, controls the characteristic of described write transistor.

In brief, the characteristic of the technical controlling write transistor disclosed in this specification, and therefore, it is possible to Adjust the write capability of write transistor.Even if when the level of the video signal applied is identical, writing storage The level of the signal of capacitor also can be adjusted by the characteristic controlling write transistor.As a result, write capability can It is adjusted so that and obtains the brightness actually entering level corresponding to video signal.Then, this technology can For suppressing " luminance shortage phenomenon " in the case of high video level.

Image element circuit according to first embodiment, the display device of the second embodiment, the electricity of the 3rd embodiment Sub-device and the pixel circuit drive method of the 4th embodiment, control the characteristic of write transistor, thus be Make when the field-effect transistor with back-gate effect writes for signal, it is possible to obtain correspondence more reliably Brightness in incoming video signal level.

Accompanying drawing explanation

Fig. 1 is the block diagram of the example of the structure schematically illustrating active matrix type display；

Fig. 2 is the example of the structure schematically illustrating the active matrix type display that can show coloured image The block diagram of son；

Fig. 3 A and 3B is to aid in explaining the figure of light-emitting component (equivalence is image element circuit)；

Fig. 4 is the figure of the form illustrating the image element circuit according to the first comparative example；

Fig. 5 is the general summary of the display device illustrating and including the image element circuit according to the first comparative example Figure；

Fig. 6 is the figure of the form illustrating the image element circuit according to the second comparative example；

Fig. 7 is the general summary of the display device illustrating and including the image element circuit according to the second comparative example Figure；

Fig. 8 is the figure of the form illustrating the image element circuit according to first embodiment；

Fig. 9 is the general summary of the display device illustrating and including the image element circuit according to first embodiment Figure；

Figure 10 is to aid in explaining the sequential chart of the method driving the image element circuit according to comparative example；

Figure 11 is to aid in the figure of the principle of the measure of the luminance shortage phenomenon that explanation causes for back-gate effect, And help explain the transistor characteristic dependent figure to substrate electromotive force；

Figure 12 is to aid in explaining the sequential chart of the method driving the image element circuit according to first embodiment, wherein Attention is pointed to transistor characteristic and is controlled voltage；

Figure 13 is the figure of the form illustrating the image element circuit according to the second embodiment；

Figure 14 is the general summary of the display device illustrating and including the image element circuit according to the second embodiment Figure；

Figure 15 is to aid in explaining the sequential chart of the method driving the image element circuit according to the second embodiment, wherein Attention is pointed to transistor characteristic and is controlled voltage；

Figure 16 is the figure of the form illustrating the image element circuit according to the 3rd embodiment；

Figure 17 is the general summary illustrating the display device including the image element circuit according to the 3rd embodiment Figure；

Figure 18 is to aid in explaining the sequential chart of the method driving the image element circuit according to the 3rd embodiment, wherein Attention is pointed to transistor characteristic and is controlled voltage；

Figure 19 is the figure of the general summary illustrating the image element circuit according to the 4th embodiment；

Figure 20 is the general summary illustrating the display device including the image element circuit according to the 4th embodiment Figure；

Figure 21 is to aid in explaining the sequential chart of the method driving the image element circuit according to the 4th embodiment, wherein Attention is pointed to transistor characteristic and is controlled voltage；

Figure 22 A to 22E is to aid in explaining the figure of the 5th embodiment (electronic installation)；

Detailed description of the invention

The preferred embodiment of the technology disclosed in this specification it is described in detail in later with reference to accompanying drawing.When logical When form of crossing distinguishes each function element, each function element will with alphabetic character, " n " (n be digital), Or a combination thereof describes as the labelling being attached to each function element.Each when describing with distinguishing the most especially During function element, labelling will be omitted.For accompanying drawing too.

To illustrate in the following order.

1. summary

2. the summary of display device

3. light-emitting component

4. driving method: basis

5. the object lesson of application: illustrate that the brightness caused by back-gate effect lacks phenomenon

First embodiment: basis (controls the backgate of write transistor)

Second embodiment: write pulse is coupled to backgate by capacity cell

3rd embodiment: video signal is coupled to backgate by capacity cell

4th embodiment: write pulse is coupled to backgate by buffer

5th embodiment: the example of the electronic installation of application

First basic point below will be described.

In the structure of the present embodiment, image element circuit, display device or electronic installation include: display part Point；Storage capacitor；For would correspond to video signal driving voltage write storage capacitor write crystalline substance Body pipe；And driving transistor, drive display part for driving voltage based on write storage capacitor. In image element circuit, display device, electronic installation and the side driving image element circuit (or display device) In method, to write what the process operation of storage capacitor associated with the driving voltage that would correspond to video signal Mode, controls the characteristic of write transistor.By to control by the way of associating with signal writing operation to write crystal The characteristic of pipe adjusts the write capability of write transistor.Therefore, even when the level of the video signal applied Time identical, the level of the signal of write storage capacitor also can be adjusted.Owing to adjustable write capability is to obtain The brightness of the level of applied video signal must be corresponded to, so even imitating when the field with back-gate effect When answering transistor to be used for signal write, it is possible to obtain video signal corresponding to being applied more reliably The brightness of level.

Preferably, image element circuit includes Characteristics Control part, for with would correspond to driving of video signal Galvanic electricity pressure writes the mode processing operation association of storage capacitor, controls the characteristic of described write transistor.

In order to realize " to write the process behaviour of storage capacitor with the driving voltage that would correspond to video signal Make the mode associated, control the characteristic of write transistor ", specifically, would correspond to the driving of video signal The write capability increasing write transistor in the period of the process of voltage write storage capacitor is sufficient for.

More specifically, preferably the process of storage capacitor is write with the driving voltage that would correspond to video signal Beginning increase the write capability of write transistor simultaneously.I.e., especially, opening when the write capability of write transistor When the moment of beginning signal write increases, it is thus achieved that well effect.Need not signal write process whole Period increases the write capability of write transistor.

An aspect according to transistor characteristic, preferably writes with the driving voltage that would correspond to video signal The beginning of the process of storage capacitor reduces the threshold voltage of write transistor simultaneously.I.e., especially, when writing The threshold voltage of transistor is when the start time that signal writes reduces, it is thus achieved that well effect.Work as threshold value When voltage declines, the write capability of write transistor can be increased.Need not signal write process whole time The threshold voltage of write transistor is reduced in Duan.

Preferably, use has the transistor of the Characteristics Control terminal that can control threshold voltage as writing crystalline substance Body pipe.In this case, the control signal controlling threshold voltage is applied to Characteristics Control terminal.

Such as, back of the body gate type thin film transistor or MOSFET(metal oxide film field-effect transistor) close It is useful as the transistor with the Characteristics Control terminal that can control threshold voltage.Particularly preferably use MOSFET。

When the transistor with the Characteristics Control terminal that can control threshold voltage is used as write transistor, Can use constructed as below as first example, wherein, at Characteristics Control terminal and the control electricity of write transistor Disposing capacity cell between extreme son, the control electrode terminal of write transistor is provided for controlling writes crystal The control signal of the conduction/non-conduction of pipe.

When the transistor with the Characteristics Control terminal that can control threshold voltage is used as write transistor, Can use constructed as below as second example, wherein, at Characteristics Control terminal with for transmission video signal Video signal cable between dispose capacity cell.

First example or second example preferably include time constant adjustment member, are used for passing through capacity cell Adjust the time constant of the signal being applied to Characteristics Control terminal.Time constant adjustment member can have connection Resistive element to Characteristics Control terminal.That is, can be for providing signals to characteristic by capacity cell On circuit (wiring) path of control terminal, resistive element is set.Line resistance when Characteristics Control terminal When there is less resistance value and by the coupling of capacity cell, there is less effect, when being suitable for application Between constant adjustment member.Specifically, when the time constant limited by capacity cell and Characteristics Control terminal Line resistance less, and when the application time of coupled voltages is shorter, in the start time of signal write The effect of the write capability increasing write transistor may be not enough.In such a case, for writing at signal Start time increase write transistor write capability period can by time constant adjustment member increase time Between constant extend.But, in this case, at time constant adjustment member and Characteristics Control terminal Line resistance between formed bleeder circuit.Accordingly, it is considered to the Characteristics Control being applied to write transistor The decline of the level of the characteristic control signal of terminal, is preferably provided with being formed the parts of time constant adjustment member The constant (constant) of (such as resistive element).

When the transistor with the Characteristics Control terminal that can control threshold voltage is used as write transistor, can Use constructed as below as third example, wherein, corresponding to the conduction/non-conduction for controlling write transistor The pulse signal of control signal be applied to Characteristics Control terminal.Although third example and first case subclass Seemingly, but the difference of third example and the first particle is characterized in particular in corresponding to for controlling write transistor The pulse signal of the control signal of conduction/non-conduction is applied to the characteristic of write transistor by buffer Control terminal.

In the 3rd situation, this structure preferably includes pulse width adjustment member and is applied to spy for adjusting At least one in the amplitude adjustment member of the amplitude of the signal of property control terminal, this pulse width adjustment portion Demultiplexing controls the pulse width of the control signal of the conduction/non-conduction of write transistor and is executed by signal in adjustment Being added to Characteristics Control terminal, write transistor is arranged in conducting state (p17) by this pulse width.Obtain With first example and second example similar purpose, it preferably has time constant adjustment member.Differential electricity (differentiating circuit) can be used as pulse width adjustment member, and resistor voltage divider circuit on road (resistance dividing circuit) can be used as amplitude adjustment member.Resistor voltage divider circuit can use as follows Structure a: terminal of a resistive element is connected to the Characteristics Control terminal of write transistor, and this spy The line resistance of property control terminal is used as another resistive element.

Device structure can include an image element circuit (display part), or can include pixel portion, at this Pixel portion arranges display part with the form of line or two-dimensional matrix.Including the structure of pixel portion In, Characteristics Control part preferably controls the characteristic of the write transistor in each display part.Including pixel Part, with two-dimensional matrix form arrange display part structure in, Characteristics Control part can by scanning The characteristic of the write transistor in each display element of processing controls.By way of parenthesis, when in each display element When performing to control, the trap (well) of write transistor separates preferably independently of one another.As by-line (on a Line-sequential basis) when performing light emitting control, often go separation trap gesture (well in (or each column) Potential) (transistor characteristic control signal) is sufficient for, and is at least often going in (or each column) The trap separating write transistor is sufficient for, but is not excluded for separating the trap of the write transistor in each display element.

Including emissive type luminous component, (such as organic electroluminescence emission part divides, inorganic EL is sent out Light part, LED luminous component and semiconductor laser light emitting part) light-emitting component (display element) Can be used as display part.Display part dtex does not preferably include organic electroluminescent luminous component.

In the following description, the resistance value of circuit structure parts, capacitance (electric capacity) etc. are available is attached to The same reference numerals mark of parts, in order to simplify corresponding understanding.

[basic]

First the summary of the display device including light-emitting component is introduced.

In the following description of circuit structure, " electrical connection " will be briefly described as " connection ".Should " electricity Connect " not only include being directly connected to, also include that (its typical example is switch by other transistor Transistor) or other electric device (it is not limited to active component and can be also passive element) connect.

Display device includes multiple image element circuit (it also may be simply referred to as pixel).Each image element circuit has bag Include the display element (electrooptic cell) of luminous component and be used for the drive circuit of driven for emitting lights part.Such as, Including emissive type luminous component, (such as organic electroluminescence emission part divides, inorganic EL illuminating part Point, LED luminous component and semiconductor laser light emitting part) light-emitting component can be used as display part. By way of parenthesis, the driving system of constant current is used as driving the system of the luminous component of display element.But, To be not limited to constant current driving for this system in principle, can be also that constant voltage is driving.

In following example to be introduced, organic electroluminescence emission part divides and is included as light-emitting component.More Concrete, light-emitting component is organic electroluminescent device (organic EL element), and it has by stacking (laminate) drive circuit and the organic electroluminescence emission part being connected to drive circuit divide (luminous component ELP) structure formed.

The drive circuit of driven for emitting lights part ELP includes multiple circuit.And, image element circuit can include The drive circuits such as 5Tr/1C type, 4Tr/1C type, 3Tr/1C type, 2Tr/1C type.In " α Tr/1C type " Middle α represents the number of transistor." 1C " represents that capacitive part includes a storage capacitor C_CS(electric capacity Device).The transistor of each formation drive circuit is preferably n-channel transistor, but is not limited to this.? In certain situation, a part of transistor can be p-channel-type.Subsidiary, transistor may be formed at quasiconductor In substrate etc..Formed drive circuit transistor structure without particular limitation of, can use by MOS type FET The isolated-gate field effect transistor (IGFET) that (general thin film transistor (TFT) (TFT)) represents.Drive it addition, formed The transistor of circuit can be any one in enhancement mode or depletion type, or can be single grid-type or double grid Any one in type.

In any configuration, display device substantially includes luminous component ELP, drives transistor TR_D, write Transistor TR_W(also referred to as sampling (sampling) transistor), at least include writing the vertical of sweep test Sweep test, the horizontal driving section with the function of segment signal output and storage capacitor C_CS, as As minimum element in the case of 2Tr/1C type.Preferably, in order to form bootstrapping (bootstrap) Circuit, storage capacitor CCS is connected to drive transistor TR_DControl input terminal (gate terminal) With driving transistor TR_DOne of main electrode terminal (source/drain region) (being typically source terminal) between. Drive transistor TR_DA main electrode terminal be connected to luminous component ELP, and drive transistor TR_DAnother main electrode terminal be connected to power supply (power supply) line PWL.From power circuit, use Scanning circuits in supply voltage etc. apply supply voltage (steady state voltage or impulse form voltage) to electricity Source line PWL.

Horizontal driving section provides has the video signal VS of broad sense to video signal cable DTL, this video Signal represents the video signal V for controlling the brightness in luminous component ELP_sigAnd for threshold correction Reference potential (it is not necessarily one) etc..Write transistor TR_WA main electrode terminal be connected to Video signal cable DTL, and write transistor TR_WAnother main electrode terminal be connected to drive transistor TR_DControl input terminal.Write sweep test and will be used for transistor TR by writing scan line WSL_W's The control pulse that ON/OFF (on/off) controls is applied to write transistor TR_WControl input terminal.Write crystalline substance Body pipe TR_WMain electrode terminal another terminal, drive transistor TR_DControl input terminal and deposit Storage capacitor C_CSA terminal between junction point will be referred to as primary nodal point ND₁.Drive transistor Device TR_DA main electrode terminal and storage capacitor C_CSAnother terminal between junction point will be claimed It is the second node ND₂。

The structure of example

Fig. 1 and Fig. 2 illustrates the active array type display dress of the embodiment such as the display device according to the disclosure The block diagram of the summary of the example of the structure put.Fig. 1 is the structure illustrating common active matrix type display The block diagram of the summary made.In the case of Fig. 2 is for providing coloured image to show, the frame of the summary of display device Figure.

As it is shown in figure 1, display device 1 includes: display surface plate 100, in display surface plate 100, Arrange have organic EL element (not shown) as multiple display elements image element circuit 10(also referred to as Pixel), in order to formed and there is X:Y(such as 9:16) display aspect ratio (aspect ratio) effective Video area；Signal generator is driven to divide 200(so-called timing generator), it is used for driving as generation The example that the panel control section of the various pulse signals controlling display surface plate 100 divides；And video signal Process part 220.In the present example, signal generator is driven to divide 200 and video signal processing section 220 It is contained in a chip IC (integrated circuit), and drives signal generator to divide 200 and video signal Process part 220 and be positioned in the outside of display surface plate 100.

Subsidiary, as product form, display device 1 is not limited to be provided as module (ingredient) Display device 1 in form, this modular form includes all of display surface plate 100, drives signal to produce Part 200 and video signal processing section 220, as shown in FIG., but such as display surface plate 100 can be provided separately as display device 1.It addition, display device 1 also includes sealing (sealed) The display device of modularity (modular) form of structure.Such as by by the back side of clear glass etc. (counter) display module being partly laminated to pixel array portion 102 and formed is corresponding to this display Device.Transparent backsides part can be set chromatic filter, protecting film, photomask etc..In order to from outside Input or output video signal Vsig and various driving pulse are to pixel array portion 102, display module Circuit part and FPC(flexible print circuit can be provided with) etc..

This display device 1 can be used as the display part in various electronic installation, i.e. electricity in all spectra Sub-device, it is by the video signal exporting electronic installation or the video signal produced in an electronic It is shown as rest image or mobile image (video), such as, uses and include semiconductor memory, small-sized The record portable music player of medium, digital camera, the notes such as disk (MD), cassette tape This PC, the mobile communication terminal including portable phone etc. and video camera.

Display surface plate 100 is included therein with the matrix arrangement image element circuit 10 of M row × N row Pixel array portion 102, in the vertical driving section 103 of vertical scan direction image element circuit 10, Horizontal driving section 106(for scanning element circuit 10 in the horizontal direction be also known as horizontal selector or Person's data-line drive part), in each drive part (vertical driving section 103 and horizontal drive portion Points 106) and the interface section 130 etc. of interface of external circuit, pixel array portion 102, vertically drive Dynamic part 103, horizontal driving section 106, interface section 130, terminal part 108 etc. are integrated and shape Become in substrate 101.That is, peripheral drive circuit (such as vertical driving section 103, horizontal drive portion Points 106, interface section 130 etc.) it is formed in same substrate 101 as pixel array portion 102. In Fig. 1 by 10_N, M mark be positioned at m row (m=1,2,3 ..., M) and n-th arrange (n=1, 2,3 ..., N) light-emitting component (image element circuit 10).

Interface section 130 has the vertical IF portion of the interface at vertical driving section 103 and external circuit Points 133 and the horizontal IF part 136 of interface at horizontal driving section 106 and external circuit.

Vertical driving section 103 and horizontal driving section 106 are formed and control part 109, control part 109 For control signal electromotive force to the storage write of capacitor, threshold correction operation, mobility (mobility) Correct operation and bootstrapping operation.Formed for driving the image element circuit controlled in pixel array portion 102 The driving control circuit of 10, this driving control circuit includes controlling part 109 and interface section 130(hangs down Straight IF part 133 and horizontal IF part 136).

In the case of 2Tr/1C type, vertical driving section 103 includes that writing sweep test (writes scanning device WS；Write scanning) and be used as have supply of electric power ability voltage sweep device driving sweep test (drive Scanning device DS；Drive scanning).As an example, by vertical driving section 103 from the level side of Fig. 1 Side upwards or both sides drive pixel array portion 102, and by horizontal driving section 106 from Side or both sides in the vertical direction of Fig. 1 drive pixel array portion 102.

Terminal part 108 is applied to the driving signal generator on the outside being arranged on display device 1 Divide the various pulse signals of 200.Terminal part 108 is applied from video signal processing section similarly The video signal Vsig of 220.When provide colour display time, terminal part 108 be applied in different colours ( In this example, R(is red), G(green) and B(blue) three primary colours) and video signal V_{sig_R}, video letter Number V_{sig_G}And video signal V_{sig_B}。

As an example, necessary pulse signal is applied as the pulse signal for vertical drive, this pulse The displacement of the example that signal such as starts pulse as scanning in vertical direction starts pulse (shift Start pulse) SP(two kinds, i.e. SPDS and SPWS in Fig. 1) and vertical scanning clock CK (two kinds, i.e. CKDS and CKWS in Fig. 1), the vertical scanning clock of phasing back as required XCK(two kinds, i.e. xCKDS and xCKWS in Fig. 1) and in particular moment marker pulse The enabling pulse of output.Apply necessary pulse signal as horizontal drive pulse signal, this pulse signal The level of the example such as starting pulse as scanning in the horizontal direction starts pulse and horizontal sweep The horizontal sweep clock xCKH of clock CKH, as required phasing back and in particular moment The enabling pulse of marker pulse output.

Each terminal of terminal part 108 passes through connection to vertical driving section 103 and horizontal drive Part 106.Such as, each pulse of terminal part 108 it is applied to as desired by not shown in figure Level displacement shifter partial interior adjust voltage level, and then each pulse is applied by buffer To vertical driving section 103 and each part of horizontal driving section 106.

Not shown although (will be described in detail below), in pixel array portion 102, in the matrix form The pixel with pixel transistor provided as the organic EL element of display element is provided two-dimensionally Circuit 10.For pixel arrange each row arrange vertical scan line SCL, and for pixel layout each Row arrange video signal cable DTL.That is, image element circuit 10 is connected to vertically by vertical scan line SCL Drive part 103, and image element circuit 10 is connected to horizontal driving section by video signal cable DTL 106.Especially, for each pixel column of the image element circuit 10 of matrix arrangement, arrange for by Vertical scan line SCL_1 to the SCL_M of the m row that vertical driving section 103 is driven by driving pulse. Vertical driving section 103 is formed by the combination of gate (including latch, shift register etc.).Base Next self-driven signal generator in vertical drive system divides the pulse signal of 200, vertical driving section 103 The image element circuit 10 of the pixel array portion 102 in alternative column unit, i.e. by vertical scan line SCL even Continuous selection image element circuit 10.Horizontal driving section 106 (is included latch, shift register by gate Deng) combination formed.Next self-driven signal generator based on horizontal driving system divides the pulse of 200 to believe Number, the image element circuit 10 of the pixel array portion 102 in horizontal driving section 106 alternative column unit, i.e. Make the selected image element circuit 10 predetermined potential by video signal cable DTL sample video signal VS (such as adaptation signal V_sigLevel) and by electromotive force write storage capacitor C_CS。

Display device 1 according to the present embodiment can by-line (line-sequential) drive or pointwise (dot-sequential) drive.The writing sweep test 104 and drive sweep test of vertical driving section 103 105 by-lines (that is, with behavior unit) scanning element array portion 102, and Tong Bu with this, and level is driven Dynamic part 106 is by (in the case of by-line drives) while of a horizontal picture signal or with pixel For in unit (in the case of pointwise drives) writing pixel array portion 102.

As in figure 2 it is shown, such as in order to coloured image shows, pixel array portion 102 has predetermined The image element circuit 10 of the vertical bar form of arrangement order_R, image element circuit 10_GWith image element circuit 10_BAs not Same color (in the present example, R(is red), G(are green) and B(blue) three primary colours) and sub-pixel. One sub-collection of pixels of different colours forms a colour element.Although illustrating in this case to hang down Vertical bar form arranges the bar structure example as subpixel layouts of the sub-pixel of each color, sub-pixel cloth Office is not limited to the example of this layout.Also can use the form of displacement sub-pixel in vertical direction.

Subsidiary, although Fig. 1 and Fig. 2 illustrates have the side being arranged only at pixel array portion 102 Vertical driving section 103(is specially the element of vertical driving section 103) structure, but can be The element of vertical driving section 103 is all arranged on the left side of insertion pixel array portion 102 therebetween and right side. It addition, the one of vertical driving section 103 may be arranged on corresponding left side and right side with other elements. It is similar to, although Fig. 1 and Fig. 2 illustrates the water having on the side being arranged only at pixel array portion 102 The structure of flat drive part 106, but can be in the upper side and lower side of the pixel array portion 102 inserted therebetween All arrange horizontal driving section 106.Although in the present example from the outside input arteries and veins of display surface plate 100 (such as vertical displacement starts pulse, vertical scanning clock, level starts pulse and level is swept to rush signal Retouch clock), but the driving signal generator for producing these various commutator pulses divide 200 may be provided at aobvious Show in panel block 100.

Structure shown in figure is merely representative of a kind of form of display device.Can take other form as product Product form.In other words, whole display device is formed to include being sufficient for lower part, i.e. includes having Form the pixel array portion of the element of the image element circuit 10 arranged in the matrix form, be arranged in pel array The control part (as major part) of portion, is connected to drive the scanning of the scan line of each pixel Partly and for producing the driving signal generator of the various signals of operation control part divide and video letter Number process part.As product form, (this form is referred to as plate not only can to use the form shown in figure Upper layout constructs), in form shown in the figure, have and be arranged on same substrate (such as substrate of glass) On pixel array portion and control part display surface plate with drive signal generator divide and video signal Process part separately, and (this form is referred to as the layout structure of peripheral circuit outside plate also can to use following form Make): pixel array portion is arranged in display surface plate, and peripheral circuit (such as control part, drives Dynamic signal generator divides and video signal processing section) it is arranged on the substrate (example separated with display surface plate Such as flexible board) on.It addition, by pixel array portion and control part are arranged on the same base And formed and arrange in the case of structure on the plate of display surface plate, (this form will claim can to use following form For the integrated structure of transistor): in the process that pixel array portion is formed TFT, concurrently form control portion Divide each transistor of (driving signal generator to divide and video signal processing section as required), and Following form (this form is referred to as COG and arranges structure) can be used: be used for controlling part (and such as institute The driving signal generator needed divides and video signal processing section) semiconductor chip by COG(glass Upper chip) technology of setting is set directly on it and is provided with in the substrate of pixel array portion.Alternatively, Can only provide display surface plate (at least including pixel array portion) as display device.

<light-emitting component>

Fig. 3 A and 3B is to aid in explaining that the light-emitting component 11(equivalence including drive circuit is image element circuit 10) figure.Fig. 3 A is light-emitting component 11(image element circuit 10) the imperfect cross section of signal of part regard Figure.Fig. 3 B is the cross sectional view of the example of mos transistor structure.Assume the insulated gate field in Fig. 3 A Effect transistor is thin film transistor (TFT) (TFT).But, as below by will described in example described in, In the present embodiment, the MOS transistor phase shown in so-called back of the body gate type thin film transistor or Fig. 3 B Hope and be at least used as write transistor TR_W.MOS type shown in Fig. 3 B is particularly suited for use as write transistor TR_W.This is because the thin film transistor (TFT) of back of the body grating structure relates to complex fabrication process (or being difficult to manufacture), But in the MOS type shown in figure 3b, first semiconductor base or trap play backgate (also referred to as Block (bulk)) effect.

As shown in Figure 3A, each transistor and the capacitance part of the drive circuit of light-emitting component 11 are such as formed Divide (storage capacitor C_CS) be formed on supporter (support) 20, and luminous component ELP shape Become and forming each transistor and the storage capacitor C of drive circuit_CSTop, wherein interlayer insulative layer 40 It is inserted in luminous component ELP and each transistor and storage capacitor C_CSBetween.Drive transistor TR_DOne of source/polar region be connected to arrange the anode electrode of luminous component ELP by contact hole.Figure 3A and 3B only illustrates driving transistor TR_D.View conceals write transistor TR_WCrystal with other Pipe.Luminous component ELP has known structure and structure, including such as anode electrode, hole transport layer, Luminescent layer, electron transfer layer and cathode electrode.

Concrete, drive transistor TR_DIncluding gate electrode 31, gate insulation layer 32, semiconductor layer 33, The source/drain region 35 being arranged in semiconductor layer 33 and channel formation region 34, between source/drain region 35 Semiconductor layer 33 correspond partly to this region 34.Storage capacitor C_CSBy another electrode 36, by grid Dielectric layer and an electrode 37(that the extension of insulating barrier 32 is formed correspond to secondary nodal point ND₂) Constitute.Gate electrode 31, the part of gate insulation layer 32 and formation storage capacitor C_CSAnother electrode 36 are formed on supporter 20.Drive transistor TR_DA source/drain region 35 be connected to circuit 38. Another source/drain region 35 is connected to this electrode 37.Drive transistor TR_D, storage capacitor C_CSDeng Covered by interlayer insulative layer 40.By anode electrode 51, hole transport layer, luminescent layer, electron transfer layer with And the luminous component ELP that cathode electrode 53 is constituted is arranged on interlayer insulative layer 40.In figure 3 a, Hole transport layer, luminescent layer and electron transfer layer is represented by a layer 52.Second interlayer insulative layer 54 It is arranged in the part of interlayer insulative layer 40, is not provided with luminous component ELP on the portion.Transparent substrates 21 are arranged on the second interlayer insulative layer 54 and cathode electrode 53.Transmitted in luminescent layer by substrate 21 The light produced, and outside will be output this light to.This electrode 37 and anode electrode 51 are by setting The contact hole put in interlayer insulative layer 40 is connected to each other.Cathode electrode 53 is by contact hole 56 and connects Contact hole 55 is connected to the circuit 39 being arranged on the extension of gate insulation layer 32, and this contact hole 55 sets Put in the second interlayer insulative layer 54 and interlayer insulative layer 40.

In structure shown in figure 3 a, when TFT is MOS transistor, as shown in Figure 3 B, grid (narrow region raceway groove) is formed at partly leading of the first polarity (p-type or N-type (for N-type in Fig. 3 B)) On the surface of body substrate, and it is attached gate terminal so that with the oxidation being inserted between gate terminal and raceway groove Film (particularly referred to as gate oxidation films) covers raceway groove.Such as polysilicon can be used as the material of gate terminal, and It is specifically referred to as polysilicon gate (poly-gate).It addition, form oxide-film (particularly referred to as field oxide film), The entirety of gate terminal is included to cover, and the second polarity that hereafter attachment is different from the first polarity ( This situation is p-type) source region and each terminal (respectively source terminal and the drain terminal) conduct in drain region The metal material at gate terminal two ends.Therefore, the MOS of the second polarity (being p-type in this case) is brilliant Body pipe (PMOS) (P-type device) is formed at the surface layer of the semiconductor base of the first polarity (N-type) In.Backgate in the P-type device of this structure is N-type substrate, and this backgate is not individually separated. The signal that may not perform individually or often with going (or each column) separate P-type device applies, but can To apply the control signal common to all P-type device of pixel array portion 102.In order in the first pole Property (N-type) semiconductor base surface layer in form the first polarity (in situation for N-type) MOS transistor (NMOS) (N-type device), at the table of the semiconductor base of the first polarity (N-type) Face forms the trap of the second polarity (p-type), and then using this trap (p-well) as the second polarity (p-type) Semiconductor base and be similarly constructed grid region, source region, drain region etc. and be sufficient for.The N-type device of this structure The trap of the second polarity (p-type) in part can separate individually or often with going (or each column), and because of This can separate trap electromotive force (transistor characteristic control signal Vb) individually or often with going (or each column). Subsidiary, the surface layer of the semiconductor base of the first polarity (N-type) forms the second polarity (at this Situation is p-type) MOS transistor (PMOS) (P-type device) in, the first polarity (N-type) The trap semiconductor base that may be formed at the first polarity (N-type) surface in (seeing the dotted line in Fig. 3 B), And hereafter this trap (N trap) can be regarded as the first polarity (N-type) semiconductor base and similarly Form grid region, source region, drain region etc..Then, can individually or often with going (or each column) separately The trap of the first polarity (N-type) in the P-type device of this structure, and therefore can individually or often go (or each column) ground separately trap electromotive force (transistor characteristic control signal Vb).Pass through element isolation region P-type device (PMOS) and N-type device (NMOS) are separated from each other.

The method of driven for emitting lights part explained below.In order to make it easy to understand, assume by n-channel type brilliant The tubular each transistor being shaped as image element circuit 10 of body is introduced.In addition, it is assumed that luminous component The anode terminal of ELP is connected to the second economize on electricity ND₂, and the cathode terminal of luminous component ELP is connected to Cathode circuit cath(assumes that the electromotive force of cathode circuit cath is cathode potential V_cath).It addition, according to drain electrode Electric current I_dsThe size of value control the luminance (brightness) in luminous component ELP.At light-emitting component In luminance, drive transistor TR_D(an illuminating part of two main electrode terminals (source/drain region) Divide the anode-side of ELP) it is used as source terminal (source region), and another is as drain terminal (drain region).False If display device colored can show and include (N/3) × M the pixel electricity arranged with two-dimensional matrix form Road 10, and assume that the image element circuit forming a color display unit includes three sub-pixel circuits (launch the red light emitting pixel circuit 10 of HONGGUANG_R, launch the green light emitting pixel circuit 10 of green glow_G, launch indigo plant The blue light emitting pixel circuit 10 of light_B).Assume that by-line drives the light-emitting component forming each image element circuit 10, And assume that display frame frequency is FR(number/second).That is, m row (wherein m=1,2,3 ..., M) arrange (N/3) individual image element circuit 10, more specifically, simultaneously drive and form N number of pixel electricity respectively The light-emitting component on road 10.In other words, control to be formed the transmitting/no of the light-emitting component of a line with behavior unit The timing launched, these light-emitting components belong to this line.Subsidiary, video signal is write formation a line The process of image element circuit 10 can be video signal is simultaneously written to the process of all image element circuits 10 (should Process also referred to as will write process simultaneously), or can be that video signal is sequentially write each image element circuit The process (this process is referred to as sequential write and processes) of 10.According to the structure of drive circuit, properly select one Individual write process and be sufficient for.

Driving operation about the light-emitting component being positioned at m row and the n-th row explained below.Subsidiary, Be positioned at the light-emitting component of m row and the n-th row will be referred to as the (n, m) light-emitting component or the (n, M) light-emitting component image element circuit.When for being arranged in the horizontal sweep of each light-emitting component of m row Section is before (m horizontal sweep period) terminate, perform multiple process (threshold correction processes, write process, Mobility (mobility) correction process etc.).Subsidiary, write process and mobility correction process needs The m horizontal sweep period performs.On the other hand, according to the type of drive circuit, at threshold correction Reason and the pretreatment processed with threshold correction can perform before the m horizontal sweep period.

After each process described above all completes so that it is each that formation is arranged in m row The luminous component of light-emitting component is luminous.Subsidiary, can make luminous component after each process all completes Luminous immediately, or make luminous component through scheduled time slot (example after all of multiple process complete The horizontal sweep period such as predetermined number of lines) time luminous.Specification (specification) according to display device, Image element circuit 10(i.e. drive circuit) structure etc. suitably set " scheduled time slot " and be sufficient for.Hereinafter, Introduce for convenience, it is assumed that make luminous component luminous immediately after multiple process complete.Formed and arrange The luminescence of the luminous component of each light-emitting component in m row proceeds to just for being arranged in Before the horizontal sweep period of each light-emitting component in (m+m ') row starts.Setting according to display device Meter specification determines that " m ' " is sufficient for.That is, formed in the m row that is arranged in particular display frame is each The luminescence of the luminous component of light-emitting component proceeds to (m+m '-1) till the horizontal sweep period.The opposing party Face, the m horizontal sweep started to next one display frame of (m+m ') horizontal sweep period from the Process of writing in period completes with mobility correction process, forms each luminous unit being arranged in m row The luminous component of part keeps non-emitting states in principle.(this period also will the period assuming non-emitting states It is referred to as the non-emissive period) to reduce image retention adjoint in driven with active matrix fuzzy (afterimage blur), And therefore obtain the most mobile picture quality.But, each image element circuit 10(light-emitting component) Emission state/non-emitting states is not limited to state described above.The time span of horizontal sweep period is little In (1/FR) × (1/M) second.When the value of (m+m ') is more than M, locate in next one display frame The horizontal sweep period that reason exceedes.

(on) state (conducting state) of opening of transistor refers to the main electrode terminal (source/drain at transistor District) between form the state of passage, and it is main not consider whether electric current flows to another from a main electrode terminal Electrode terminal.Pass (off) state (nonconducting state) of transistor refers to the main electrode end at transistor The state of passage is not formed between son.It is connected to the special transistor of the main electrode terminal of another transistor The state of main electrode terminal includes following form: the source/drain region of this special transistor and another transistor Source/drain region occupies identical region.It addition, source/drain region not only can be by such as comprising the polysilicon of impurity or non- The conductive materials of crystal silicon etc. is formed, also can be by metal, alloy, conducting particles, its stepped construction or have The layer that machine material (conductive polymer) is made is formed.In the sequential chart of middle use introduced below, instruction The length (time span) of the axle of the abscissa of each period is schematic, does not indicates that each period The ratio of time span.

The method driving image element circuit 10 includes that pre-treatment step, threshold correction process step, video signal Write process step, mobility aligning step and step of transmitting.Pre-treatment step, threshold correction process step Suddenly, video signal writes process step, mobility aligning step will be collectively known as non-emissive step.Foundation The structure of image element circuit 10, video signal writes process step and mobility aligning step can perform simultaneously.Will The summary of each step is described.

Subsidiary, according to below equation (1), the driving transistor in the luminance of driven for emitting lights element TR_D, in order to by drain current I_ds.Drain current I_dsFlow through luminous component ELP, thus luminous component ELP launches light.It addition, according to drain current I_dsThe size of value control the luminescence in luminous component ELP State (brightness).In the luminance of light-emitting component, drive transistor TR_DTwo main electrode terminals One (the anode terminal side of luminous component ELP) in (source/drain region) is used as source terminal (source region), Another is used as drain terminal (drain region).Introduce for convenience, in introduced below, drive transistor TR_D A main electrode terminal can be simply referred as source terminal, and another main electrode terminal can be simply referred as Drain terminal.

I_ds=k·μ·(V_gs–V_th)²(1)

Wherein k is coefficient k ≡ (1/2) (W/L) C_OX, L is channel length, and W is channel width, And C_OXIt is equivalent capacitance value ((relative dielectric constant of gate insulation layer) × (dielectric constant of vacuum) / (thickness of gate insulation layer)), μ is effective mobility, V_gsIt it is electromotive force (the grid electricity controlling electrode terminal Gesture V_g) and electromotive force (the source electromotive force V of source terminal_sElectric potential difference (gate source voltage) between), and V_th It it is threshold voltage.

In described below, except as otherwise noted, it is assumed that the electric capacity of the parasitic capacitance of luminous component ELP Value C_elWith storage capacitor C_CSCapacitance C_CSWith as drive capacitor TR_DThe example of parasitic capacitance It is sufficiently large value that gate-source capacitance value Cgs of son compares, and does not consider based on driving transistor TR_D Gate terminal electromotive force (gate potential V_g) change and cause drive transistor TR_DSource region (secondary nodal point ND₂) electromotive force (source voltage V_s) change.

[pre-treatment step]

Primary nodal point initialization voltage (V_ofs) it is applied to primary nodal point ND₁And the second economize on electricity initializes electricity Pressure (V_ini) it is applied to secondary nodal point ND₂, thus primary nodal point ND₁With secondary nodal point ND₂Between Electric potential difference exceedes driving transistor TR_DThreshold voltage V_th, and it is supplied to the of luminous component ELP Two node ND₂With the electric potential difference between cathode electrode is less than the threshold voltage V of luminous component ELP_thEL。 Assume such as to control the video signal V of the brightness in luminous component ELP_sigIt is 0 to 10 volts, power supply electricity Pressure is 20 volts, drives transistor TR_DThreshold voltage V_thIt is 3V, cathode potential V_cathIt it is 0 volt Spy, and the threshold voltage V of luminous component ELP_thELIt it is 3 volts.In this case, it is assumed that initial Change and drive transistor TR_DElectromotive force (the gate potential V of control input terminal_g, i.e. primary nodal point ND₁Electricity Gesture) electromotive force V_ofsIt is 0 volt, and assumes to initialize driving transistor TR_DThe electromotive force of source terminal (source electromotive force V_s, i.e. secondary nodal point ND₂Electromotive force) electromotive force V_iniIt it is-10 volts.

[threshold correction process step]

Keeping primary nodal point ND₁Electromotive force state in, drain current I_dsThrough driving transistor TR_D, And secondary nodal point ND₂Electromotive force towards by from primary nodal point ND₁Electromotive force in deduct driving transistor TR_DThreshold voltage V_thAnd the electromotive force obtained and change.Now, after pre-treatment step, exceed logical Cross and will drive transistor TR_DThreshold voltage V_thPlus secondary nodal point ND₂Electromotive force and the voltage that obtains Voltage (supply voltage of such as fluorescent lifetime) be applied to drive transistor TR_DAnother main electrode Terminal (on the opposition side of secondary nodal point).In threshold correction processes step, primary nodal point ND₁With Two node ND₂Between electric potential difference (or drive transistor TR_DGate source voltage V_gs) close to driving Transistor TR_DThreshold voltage V_thDegree depend on the time that threshold correction processes.Thus, such as When guaranteeing that threshold correction processes enough for a long time, secondary nodal point ND₂Electromotive force reach by from first Node ND₁Electromotive force in deduct driving transistor TR_DThreshold voltage V_thAnd the electromotive force obtained, and Drive transistor TR_DIt is arranged in off status.On the other hand, such as when the time that threshold calibration processes When needs are set to shorter, the first electromotive force ND₁With the second electromotive force ND₂Between electric potential difference can be more than driving Dynamic transistor TR_DThreshold voltage V_th, and drive transistor TR_DOff status may be not arranged at In.The result processed as threshold correction, drives transistor TR_DIt is not necessary to be arranged in off status. Subsidiary, in threshold correction processes step, preferably by selection and determine electromotive force to meet formula (2) and Luminous component ELP is stoped to launch light.

(V_ofs–V_th)<(V_thEL+V_cath) (2)

[video signal writes process step]

By writing driving pulse WS, by video signal V from write scan line WSL_sigFrom video signal Line DTL is via the write transistor TR being arranged on open state_WIt is applied to primary nodal point ND₁, and first Node ND₁Electromotive force rise to V_sig.Based on primary nodal point ND₁The change (V of electromotive force_in=V_sig-V_ofs) Electric charge by substep to storage capacitor C_CS, parasitic capacitance C of luminous component ELP_elAnd driving crystal Pipe TR_DParasitic capacitance (such as gate-source capacitance C_gs).As capacitance Cel and capacitance C_CSAnd electric capacity Value C_gs(such as gate-source capacitance C_gsDeng) compare the most sufficiently large value time, secondary nodal point ND₂Electromotive force (V is changed based on electromotive force_sig-V_ofs) change less.Generally, parasitic capacitance C of luminous component ELP_el Capacitance C_elMore than storage capacitor C_CSCapacitance C_CSWith gate-source capacitance C_gsCapacitance C_gs。 Considering this, unless needed especially, not considering by primary nodal point ND₁Electromotive force change and cause second Node ND₂Electromotive force change.In this case, gate source voltage V_gsFormula (3) can be passed through represent.

V_g=V_sig

V_s≈V_ofs-V_h

V_gs≈V_sig–(V_ofs–V_th) (3)

[mobility correction process step]

When by write transistor TR_WBy video signal V_sigIt is applied to store capacitor C_CSA terminal (i.e. when corresponding to video signal V_sigDriving voltage be written to store capacitor C_CS) time, electric current passes through Drive transistor TR_DAnd storage capacitor C is provided to_CS.Such as, by from writing scan line WSL Write driving pulse WS by video signal V_sigFrom video signal cable DTL via being arranged on open state Write transistor TR_WIt is applied to primary nodal point ND₁State in, to drive transistor TR_DElectric power is provided, To feed drain current I_ds, thus change secondary nodal point ND₂Electromotive force.After scheduled time slot, Write transistor TR_DIt is arranged in off status.Assume that the electromotive force of now secondary nodal point ND2 changes into Δ V (=potential correction value or degenerative amount).The scheduled time slot performing mobility correction process is defined as The value that is pre-designed during display device design is sufficient for.Subsidiary, now, preferably determine that mobility corrects Period meets formula (2A).This stops luminous component ELP to launch light during the mobility correction period.

(V_ofs–V_th+ΔV)<(V_thEL+V_cath) (2A)

When driving transistor TR_DMobility [mu] when being higher value, increase potential correction value Δ V.When driving Dynamic transistor TR_DMobility [mu] when being smaller value, reduce potential correction value Δ V.Drive transistor TR_D Gate source voltage V_gs(primary nodal point ND₁With secondary nodal point ND₂Between electric potential difference) now can with public affairs Formula (4) represents.Gate source voltage V_gsDetermine brightness during luminescence.Potential correction value Δ V and driving crystal Pipe TR_DDrain current I_dsProportional, and drain current I_dsProportional to mobility [mu].As a result, Mobility [mu] is the highest, and value Δ V is the biggest for potential correction.Therefore, it can eliminate in each pixel current 10 The change of mobility [mu].

V_gs≈V_sig-(V_ofs-V_th)-Δ V (4)

Subsidiary, when changing an expression, when video signal is passed through write transistor TR_WIt is applied to drive crystalline substance Body pipe TR_DControl input terminal and storage capacitor a terminal time, mobility correction process can It is referred to as by driving transistor TR_DElectric current is provided the process of storage capacitor.

[step of transmitting]

By writing driving pulse WS by write transistor TR from write scan line WSL_WIt is arranged on pass shape By primary nodal point ND in state₁It is arranged on suspension (floating) state, and applies power to drive Transistor TR_D, thus by driving transistor TR_DWould correspond to drive transistor TR_DGate source voltage V_gs(primary nodal point ND₁With secondary nodal point ND₂Between electric potential difference) electric current I_dsIt is fed into illuminating part Divide ELP.Thus driven for emitting lights part ELP launches light.

[according to the difference of the structure of drive circuit]

Difference between typical types, following 5Tr/1C type, 4Tr/1C type, 3Tr/1C type and 2Tr/1C type.5Tr/1C type includes the first transistor TR₁(light emitting control transistor), for applying second The transistor seconds TR of node initializing voltage₂And for applying the 3rd of primary nodal point initialization voltage Transistor TR₃, this first transistor TR₁It is connected to drive transistor TR_DMains side on main electrode Between terminal and power circuit (power pack).The first transistor TR₁, transistor seconds TR₂With Three transistor TR₃It it is each switching transistor.The first transistor TR₁Emission period is arranged on out In state, it is arranged in off status to start the non-emissive period, in the follow-up threshold correction period again It is arranged in open state, and after the mobility correction period neutralizes (also in next emission period) It is additionally arranged in open state.Transistor seconds TR₂Only in secondary nodal point initialization period, it is arranged on out shape In state, otherwise it is arranged in off status.Third transistor TR₃Only from primary nodal point initialization period to It is arranged in open state during the threshold correction period, is otherwise arranged in off status.Write transistor TR_W? From video signal write process the period be arranged on open state during the mobility correction process period, otherwise set Put in off status.

In 4Tr/1C type, omit from 5Tr/1C type for apply primary nodal point initialization voltage the Three transistor TR₃.About video signal V_sig, sequentially apply primary nodal point from video signal cable DTL Initialization voltage.In order to primary nodal point initialization voltage being believed from video in primary nodal point initialization period Number line DTL is applied to primary nodal point, also by write transistor TR in primary nodal point initialization period_WIf Put in open state.Typically, write transistor TR_WFrom primary nodal point initialization period to mobility school Just processing the period of period is arranged in open state, is otherwise arranged in off status.

In 3Tr/1C type, from 5Tr/1C type, omit transistor seconds TR₂With third transistor TR₃。 About video signal V_sig, based on the time-division, apply primary nodal point from video signal cable DTL initialize electricity Pressure and secondary nodal point initialization voltage.In order to secondary nodal point being arranged in secondary nodal point initialization period Secondary nodal point initialization voltage, and in follow-up primary nodal point initialization period, primary nodal point is arranged To primary nodal point initialization voltage, corresponding to the voltage V of secondary nodal point initialization voltage_{ofs_H}It is applied as The electromotive force of video signal cable DTL, and the electromotive force of video signal cable DTL is then set to first segment Point initialization voltage V_{ofs_L}(=V_ofs).Corresponding to this, at primary nodal point initialization period and second section In some initialization period, write transistor TR_WIt is also disposed in open state.Typically, from secondary nodal point Initialization period to period of mobility correction process period by write transistor TR_WIt is arranged in open state, Otherwise it is disposed in off status.

Subsidiary, in 3Tr/1C type, by using video signal cable DTL to change secondary nodal point ND₂ Electromotive force.For this purpose, will storage capacitor C when design_CSCapacitance C_CSIt is set to (such as capacitance C bigger than the capacitance in other drive circuit_CSIt is capacitance C_elAbout 1/4 to 1/3). Accordingly, it is considered to, compared with other drive circuit, by primary nodal point ND₁Electromotive force change the caused Two node ND₂Electromotive force change degree bigger.

In 2Tr/1C type, from 5Tr/1C type, omit the first transistor TR₁, transistor seconds TR₂ With third transistor TR₃.About video signal V_sig, execute from video signal cable DTL based on timesharing Add primary nodal point initialization voltage.By with the first electromotive force V_{CC_H}(in 5Tr/1C type=V_CC) and the Two electromotive force V_{CC_L}(in 5Tr/1C type=V_ini) pulsed drive driving transistor TR_DMains side on Main electrode terminal, it is provided that secondary nodal point initialization voltage.Drive transistor TR_DMains side on main electricity Extreme son is set to the first electromotive force V in emission period_{CC_H}, and it is set to the second electromotive force V_{CC_L} To start the non-emissive period.Drive transistor TR_DMains side on main electrode terminal in threshold value subsequently In and after the correction period, (also in next emission period) is set to the first electromotive force V_{CC_H}.In order to Primary nodal point initialization voltage from video signal cable DTL is applied to by primary nodal point initialization period Primary nodal point, write transistor TR_WPrimary nodal point initialization period is also disposed in open state.Typical case , write transistor TR_WSetting to the period of mobility correction process period from primary nodal point initialization period Put in open state, be otherwise arranged in off status.

Subsidiary, although it is described above situations below: threshold voltage and mobility are carried out school Just process, as the change of the characteristic driving transistor but it also may only in threshold voltage and mobility One execution correction process.

Although being made that described above based on preferable example, but this technology is not limited to these examples.Formed The structure of each element of display device, display element and drive circuit described in each example It is exemplary for making with the step in the method for structure and driven for emitting lights part, and can do and suitably change Become.

It addition, write process and mobility in the operation of 5Tr/1C type, 4Tr/1C type and 3Tr/1C type Correction can perform separated from one anotherly, or mobility correction process and write process and can perform simultaneously, as In 2Tr/1C type.Concrete, by by the first transistor TR₁(light emitting control transistor) is arranged on out Via write transistor TR in state_WBy video signal V_sigIt is applied to primary nodal point just foot from data wire DTL It is enough,.

The object lesson of application

Explained below control drives transistor TR_DThreshold voltage V_thThe concrete example of application of technology Son.Subsidiary, in the display device using active matrix organic EL panel, such as, it is arranged on Panel both sides are all or the vertical overscan portion of side produces the control input terminal of transistor to be supplied to Various gate signals (control pulse), and apply this signal to image element circuit 10.It addition, use this The display device of organic EL panel can use 2Tr/1C type image element circuit 10 to reduce element number and Obtain higher definition.In view of this, below by the representative example to the application that 2Tr/1C type constructs Son illustrates.

[first embodiment]

[image element circuit]

Fig. 4 and Fig. 5 be illustrate according to for each embodiment the first comparative example image element circuit 10X with And include the figure of the composition of the display device of image element circuit 10X.In pixel array portion 102, there is root The display dress according to the first comparative example will be referred to as according to the display device of the image element circuit 10X of the first comparative example Put 1X.Fig. 4 illustrates the essential structure of (pixel).Fig. 5 illustrates that (whole display fills specific configuration Put).Fig. 6 and Fig. 7 is to illustrate the image element circuit 10Y according to the second comparative example for each embodiment And include the figure of the display device of image element circuit 10Y.Pixel array portion 102 has according to The display device of the image element circuit 10Y of two comparative examples will be referred to as the display device according to the second comparative example 1Y.Fig. 6 illustrates the essential structure of (pixel).Fig. 7 illustrates specific configuration (whole display device). Fig. 8 and Fig. 9 is to illustrate the image element circuit 10A according to first embodiment and include this image element circuit 10A The figure of composition of display device.There is in pixel array portion 102 pixel according to first embodiment The display device of circuit 10A will be referred to as display device 1A according to first embodiment.Fig. 8 illustrates (one Individual pixel) essential structure.Fig. 9 illustrates specific configuration (whole display device).Subsidiary, each In comparative example and first embodiment, it is arranged on the vertical driving section of the periphery of image element circuit 10 103 and horizontal driving section 106 be also shown in the substrate 101 of display surface plate 100.To later Other embodiments to be described also is same.

To first describe comparative example and the common part of first embodiment, wherein omit reference A, attached Figure labelling X and reference Y.Display device 1 is based on video signal V_sig(specially signal amplitude V_in) (organic EL element 127 is used as luminous component in the present example to make the electrooptic cell in image element circuit 10 ELP) light is sent.For this purpose, display device 1 in pixel array portion 102 with rectangular Include in each image element circuit 10 that formula is arranged producing at least one the driving transistor 121 driving electric current (drive transistor TR_D), be connected to drive transistor 121 control input terminal (control input terminal Exemplary be gate terminal) and drive transistor 121 the lead-out terminal (exemplary of lead-out terminal Source terminal) between storage capacitor 120(store capacitor C_CS), as be connected to drive crystal The organic EL element 127(light output part of the example of the electrooptic cell of the lead-out terminal of pipe 121 divides ELP), And be used for would correspond to signal amplitude V_inInformation write storage capacitor 120 sampling transistor 125.In image element circuit 10, produce in driving transistor 121 and keep based on storage capacitor 120 The driving electric current I of information_ds, and drive electric current I_dsOrganic EL through the example as electrooptic cell Element 127, so that organic EL element 127 sends light.

Sampling transistor 125 would correspond to signal amplitude V_inInformation write storage capacitor 120.Therefore, Sampling transistor 125 is at the input terminal (in source terminal and drain terminal) of sampling transistor 125 Accept signal potential (V_ofs+V_in), and would correspond to signal amplitude V_inInformation write be connected to sampling The storage capacitor 120 of the lead-out terminal of transistor 125 (in source terminal and drain terminal another). Certainly, the lead-out terminal of sampling transistor 125 is also connected to drive the control input terminal of transistor 121.

Subsidiary, the connecting structure of image element circuit 10 illustrated above represents most basic structure.Pixel electricity Road 10 at least includes that element described above is sufficient for, and image element circuit 10 includes except these Other element (i.e. other element) outside element.It addition, " connection " is not limited to directly connect Connect, can be also to be connected by other element.For example, it is also possible on demand connection spacing is changed Become, such as, insert switching transistor, there is the functional part etc. of specific function.Typically, dynamically control The switching transistor of display time interval (launch time) can be arranged on the outfan driving transistor 121 Between son and electrooptic cell (organic EL element 127), or it is arranged on the electric power driving transistor 121 Supply terminal (exemplary of supply of electric power terminal is drain terminal) and the electric lines of force as power circuit PWL(is power line 105DSL in the present example) between.If the pixel in this modification Circuit makes it possible to realize structure to be described and action in first embodiment (or other embodiments), These modification are also the image element circuits 10 of the embodiment realizing the display device according to the disclosure.

It addition, drive the periphery of image element circuit 10 such as to have control part 109, this control part 109 include: write sweep test 104, for being held by sequential control sampling transistor in horizontal period The by-line scanning of row image element circuit 10, would correspond to video signal V_sigSignal amplitude V_inInformation Write in each storage capacitor 120 of a line；And drive sweep test 105, export turntable driving Pulse (driven by power pulse DSL), for coordinating mutually to scan with the by-line writing sweep test 104 (coordinate) mode controls to be applied to the electricity of the power supply terminal of each driving transistor 121 of a line Source.Control part 109 and also include horizontal driving section 106, be used for performing control so that at each water At ordinary times will be at reference potential (V in section_ofs) and signal potential (V_ofs+V_inThe video signal of change between) V_sigIt is applied to sampling transistor 125 in the way of coordinating mutually with the progressive scan writing sweep test 104.

Control part 109 preferably to be carried out controlling, with by would correspond to signal amplitude V_inInformation write Sampling transistor 125 is set to nonconducting state by the time point of storage capacitor 120, stops video Signal V_sigIt is applied to drive the control input terminal of transistor 121, and performs bootstrapping operation, at this Bootstrapping operation drives the electromotive force of the control input terminal of transistor 121 and the output driving transistor 121 Change operation ground association in the electromotive force of terminal.Control part 109 the most also after sampling operation terminates The luminous starting stage started perform bootstrapping operation.That is, part 109 is controlled at signal potential (V_ofs+V_in) It is applied in the state of sampling transistor 125 be arranged in conducting state sampling transistor 125, and And hereafter sampling transistor 125 is arranged in nonconducting state so that drive the control of transistor 121 Electric potential difference between input terminal and lead-out terminal keeps constant.

It addition, control part 109 preferably control bootstrapping operation, in order to realize correction electricity in emission period The operation of the secular change in optical element (organic EL element 127).For this purpose, part is controlled 109 operations preferably realizing the secular change in correction electrooptic cell in following state, in a state, By the driving electric current I in the information kept based on memory transistor 120_dsFlow through electrooptic cell (organic EL Element 127) period in continuously sampling transistor 125 is arranged in nonconducting state, can make Voltages keep constant between control input terminal and lead-out terminal.Even when organic EL element 127 In current-voltage characteristics occur secular change time, storage capacitor 120 fluorescent lifetime bootstrapping operation also Control input terminal and the lead-out terminal driving transistor 121 is kept by the storage capacitor 120 of bootstrapping Between electric potential difference constant, thus all keep constant luminosity in all times.It addition, control portion Divide 109 preferably to be carried out control to operate to perform threshold correction, for by reference potential (=primary nodal point Initialization voltage V_ofs) it is applied to the input terminal (typical case of input terminal of sampling transistor 125 Son is source terminal) period time in make sampling transistor 125 turn on, and storage capacitor 120 in Keep the threshold voltage V corresponding to driving transistor 121_thVoltage.

If desired, would correspond to signal amplitude V_inInformation write storage capacitor 120 before, preferably The operation of this threshold correction is repeated in multiple horizontal period." if desired for " refer in this case In the threshold correction period in one horizontal period, corresponding to driving the electricity of the threshold voltage of transistor 121 Pressure can not be adequately retained in storage capacitor 120.Operate repeatedly by performing threshold correction, correspond to Drive the threshold voltage V of transistor 121_thVoltage ensure that storage capacitor 120 in.

It addition, it is furthermore preferred that before threshold correction operates, control part 109 and perform control, in order to By by reference potential (V_ofs) be applied to sampling transistor 125 input terminal period time in make Sampling transistor 125 turns on, and performs preparatory function (discharge operation and the initialization behaviour of threshold correction Make),.Before threshold correction operates, initialize control input terminal and the output driving transistor 121 The electromotive force of terminal.More specifically, across storage capacitor 120 on electric potential difference be set equal to or More than threshold voltage V_th, wherein storage capacitor 120 is connected to drive the control input of transistor 121 Between son and lead-out terminal.

Subsidiary, in the threshold correction in 2Tr/1C drives structure, control part 109 and preferably include to drive Dynamic sweep test 105, for by scan with the by-line writing sweep test 104 coordinate mutually in the way of select and Export the first electromotive force V_{CC_H}Be different from the first electromotive force V_{CC_H}The second electromotive force V_{CC_L}Each to a line Image element circuit 10, this first electromotive force V_{CC_H}For making driving electric current I_dsThrough electrooptic cell (organic EL Element 127).Then, it preferably is carried out controlling, in order to would correspond to the first electromotive force V_{CC_H}Electromotive force execute It is added to drive the power supply terminal of transistor 121 and by reference potential (V_ofs) it is applied to sampling transistor By making sampling transistor 125 turn in period time of 125, and perform threshold correction operation.And, In threshold correction preparatory function in 2TR drives structure, preferably by would correspond to the second electromotive force V_{CC_L}(=secondary nodal point initialization voltage V_ini) voltage be applied to drive transistor 121 power supply terminal And by reference potential (V_ofs) be applied to sampling transistor 125 period time in make sampling transistor 125 conductings, and control input terminal (the i.e. primary nodal point ND of transistor 121 will be driven₁) electromotive force It is initialized as reference potential (V_ofs) and lead-out terminal (the i.e. secondary nodal point of transistor 121 will be driven ND₂) electromotive force be initialized as the second electromotive force V_{CC_L}。

It is furthermore preferred that after threshold correction operates, when by making sampling transistor would correspond to first Electromotive force V_{CC_H}Voltage be applied to drive transistor 121 and by signal potential (V_ofs+V_in) be applied to In period time of sampling transistor 125 conducting and by signal amplitude V_inInformation write storage capacitor When 120, control part 109 and perform operation so that the correcting value of mobility [mu] that transistor 121 will be driven It is added in the information of write storage capacitor 120.Now, sampling transistor 125 is preferably made only will to believe Number electromotive force (V_ofs+V_in) be applied in period time on sampling transistor 125 pre-position time Turning in Duan, the period in this precalculated position is shorter than signal potential (V_ofs+V_in) it is applied to sampling transistor Period time of 125.Will be described in detail 2Tr/1C below and drive the example of the image element circuit 10 in structure.

Image element circuit 10 has the driving transistor substantially formed by n-channel thin-film field-effect transistor. It addition, image element circuit 10 includes circuit, for suppression due to the long-term degradation of organic EL element (degradation) the driving electric current I of the organic EL element caused_dsChange, i.e. be used for passing through Correct the change of the I-E characteristic of the organic EL element of the example as electrooptic cell and keep driving Electric current I_dsConstant driving signal homogenization circuit (1), and this image element circuit 10 select by realize Threshold correction function and mobility calibration function and keep driving electric current I_dsConstant drive system, is used for Prevent owing to driving the change (threshold voltage variation and mobility change) of the characteristic of transistor to cause Drive the change of electric current.

Characteristic variations (the change of such as threshold voltage, mobility etc. of transistor 121 is driven as suppression And change) to driving electric current I_dsThe method of impact, design (devise) each transistor (drives crystalline substance Body pipe 121 and sampling transistor 125) driving timing, select the driving of 2TR structure the most as former state simultaneously Circuit is as driving signal homogenization circuit (1).Image element circuit 10 has 2TR and drives structure, and Therefore there is fewer number of element and fewer number of circuit.Therefore, image element circuit 10 allows to obtain Definition that must be higher, and can be without sample video signal V in the case of degenerating_sig, thus can obtain Outstanding picture quality.

It addition, image element circuit 10 has the characteristic of the connection mode of storage capacitor 120, and formed certainly For circuit (it is the example driving signal homogenization circuit (2)), as preventing due to organic EL unit The long-term degradation of part 127 and the circuit of the change driving electric current that causes.Image element circuit 10 is characterised by Image element circuit 10 has driving signal homogenization circuit (2) realizing bootstrapping function, even as organic EL During the I-E characteristic generation secular change of element, this bootstrapping function also makes driving current constant (anti- Only drive the change of electric current).

Subsidiary, image element circuit 10 includes relating to writing gain, bootstrapping gain and mobility correction period Auxiliary capacitor 310.But, image element circuit 10 includes that auxiliary capacitor 310 is dispensable.Drive The basic controlling operation of image element circuit 10 is similar to not have the image element circuit 10 of auxiliary capacitor 310 Basic operation.

FET(field-effect transistor) it is used as each transistor, including driving transistor.In this situation In, drive the gate terminal of transistor as control input terminal, drive source terminal and the drain terminal of transistor In one (it is assumed hereinafter that driving this in the source terminal of transistor and drain terminal is source terminal) make For lead-out terminal, and drive another in the source terminal of transistor and drain terminal (it is assumed hereinafter that drive In the source terminal of transistor and drain terminal this another be drain terminal) as power supply terminal.

Concrete, as shown in Figures 4 and 5, image element circuit 10 includes driving transistor 121 and sampling Transistor 125(drives transistor 121 and sampling transistor 125 to be each n-channel-types), Yi Jizuo For launching the organic EL element 127 of the example of the electrooptic cell of light by feeding electric current.Generally, organic EL element 127 has rectification (current rectifying) characteristic, and therefore by Diode symbol table Show.Subsidiary, organic EL element 127 has parasitic capacitance C_el.In the drawings, parasitic capacitance C_elShown It is shown as and the form of organic EL element 127(diode) in parallel.

The drain terminal D driving transistor 121 is connected to for applying the first electromotive force V_{CC_H}Or the second electricity Gesture V_{CC_L}Power line 105DSL.The source terminal S driving transistor 121 is connected to organic EL element The anode terminal A(of 127 drives source terminal S and the anode tap of organic EL element 127 of transistor 121 Junction point between sub-A is secondary nodal point ND₂, and it is set to node ND122).Organic EL element The negative electrode K of 127 is connected to cathode circuit cath(its electromotive force e.g. negative electrode for applying reference potential Electromotive force V_cath, or ground (GND)), cathode circuit cath is public to all image element circuits 10. Subsidiary, cathode circuit cath can be in the monolayer (upper layer circuit) for this cathode circuit cath Only have circuit, or such as can be provided for cathode circuit being formed in the anode layer of anode line Auxiliary line, thus the resistance value of cathode circuit reduce.Auxiliary line with grid, arrange or row shape Formula is arranged on pixel array portion 102(viewing area) in, and auxiliary line is set to and upper layer line The fixed potential that road is identical.

The gate terminal G of sampling transistor 125 is connected to write scan line from write sweep test 104 104WS.The drain terminal D of sampling transistor 125 is connected to video signal cable 106HS(video signal cable DTL).The source terminal S of sampling transistor 125 is connected to drive the gate terminal G(sampling of transistor 121 Junction point between the source terminal S and the gate terminal G driving transistor 121 of transistor 125 is first segment Point ND₁, and it is set to ND121).The gate terminal G of sampling transistor 125 is applied to certainly write sweep The H retouching part 104 effectively writes driving pulse WS.Sampling transistor 125 is alternatively source terminal S and leakage The connection mode that terminal D exchanges each other.

The drain terminal D driving transistor 121 is connected to from the driving sweep test as electric power scanning device The power line 105DSL of 105.Power line 105DSL has the property that, i.e. power line 105DSL Itself have and supply power to the ability driving transistor 121.Drive sweep test 105 select and Apply the first electromotive force V of high-voltage side_{CC_H}The second electromotive force V with low voltage side_{CC_L}Give and drive transistor The drain terminal D of 121, the first electromotive force V_{CC_H}Corresponding to supply voltage, the second electromotive force V_{CC_L}(this is second years old Electromotive force V_{CC_L}Also referred to as initialization voltage or initial voltage) it is used for the preparatory function before threshold correction.

Image element circuit 10 is by using the first electromotive force V_{CC_H}With the second electromotive force V_{CC_L}Two value electric power Driving pulse DSL drives the drain terminal D side (power circuit side) of transistor 121 to perform threshold value Preparatory function before correction.Assume the second electromotive force V_{CC_L}Relative to regarding in video signal cable 106HS Frequently signal V_sigReference potential (V_ofs) of a sufficiently low.Concrete, the low electricity of power line 105DSL is set The second electromotive force V on gesture side_{CC_L}So that drive the gate source voltage V of transistor 121_gs(gate potential V_g With source electromotive force V_sBetween difference) more than drive transistor 121 threshold voltage V_th.Subsidiary, benchmark Electromotive force (V_ofs) it is used for the initialization operation before threshold correction operation, and also for precharge in advance Video signal cable 106HS.

In this image element circuit 10, when driving organic EL element 127, drive transistor 121 Drain terminal D is applied in the first electromotive force V_{CC_H}And the source terminal S driving transistor 121 is connected to organic The anode terminal A side of EL element 127, thus generally form source follower circuit.

When using this image element circuit 10, by selecting use driving transistor 121 and one to be used for sweeping The 2TR of other switching transistor (sampling transistor 125) retouched drives structure, and by arranging electricity Power driving pulse DSL and each switching transistor of ON/OFF timing controlled writing driving pulse WS, stop The long-term degradation of organic EL element 127 and changing features (the such as threshold value electricity of driving transistor 121 The change of pressure, mobility etc. and change) to driving electric current I_dsImpact.

It addition, according in display device 1A of first embodiment, incite somebody to action in each image element circuit 10A As electric capacity C_subThe auxiliary capacitor 310 of capacity cell be added to node ND122(and drive transistor 121 Source terminal S, storage one terminal of capacitor 120 and the anode terminal A of organic EL element 127 Between junction point).Another terminal (this terminal is referred to as node ND310) institute with auxiliary capacitor 310 The point being connected to is unrelated, the auxiliary capacitor 310 in circuit structure in terms of circuit with organic EL element 127 (parasitic capacitance C of organic EL element 127_el) in parallel.By way of example it is assumed that the company of node ND310 Contact be the public cathode circuit cath(of all image element circuits 10 its can be upper layer circuit or boost line Road), the cathode terminal K of all organic EL element 127 is connected to this cathode circuit.It addition, node The junction point of ND310 can be such as the power line 105DSL in this level (own stage) (OK), remove this The power line 105DSL in other level (OK) outside level (OK) or there is the fixing electricity of arbitrary value Gesture point (including earth potential).Each part as the junction point of node ND310 has the advantage that and shortcoming, The explanation to these merits and demerits will be omitted below.

Determine the capacitance C of storage capacitor 120_CSParasitic capacitance C with organic EL element 127_el's Capacitance C_el, in order to writing gain G_inWith bootstrapping gain G_bstBetween be balanced, and make each increasing Yidu is suitable gain.Can be by adjusting the capacitance C of auxiliary capacitor 310_subAnd adjust and write gain G_in With bootstrapping gain G_bst.When utilizing now, it is possible to by relatively adjusting three rgb pixel circuit 10 Between capacitance C_subAnd obtain white balance.Concrete, organic due to each color of R, G and B The luminous efficiency of EL element 127 is different from each other, so when without auxiliary capacitor 310, in equal driving Electric current I_ds(the most equal signal amplitude V_inWhite balance can not be obtained in the case of).Therefore, by not Different signal amplitude V is provided with color_inAnd obtain white balance.On the other hand, by relatively adjusting three The capacitance C of the auxiliary capacitor 310 between individual rgb pixel circuit 10_sub, even in equal driving Electric current I_dsIn the case of also can obtain white balance.Furthermore it is possible in the situation not affecting threshold correction operation Under by add auxiliary capacitor 310 adjust correction mobility [mu] needed for time.Even work as image element circuit When the driving of 10 quickly increases, it is possible to enter correction time by using auxiliary capacitor 310 to adjust mobility The mobility correction that row is enough.

[structure that first embodiment is exclusive]

It is different from the common thin film transistor (TFT) without backgate terminal, at control input terminal (gate terminal) Outside also have and can control transistor characteristic and (in this case, increase or reduce threshold voltage V_th) The transistor of control terminal (being referred to as transistor characteristic control terminal after this control terminal) be used as Image element circuit 10X according to the first comparative example and every according in the image element circuit 10Y of the second comparative example Individual transistor.The exemplary of the transistor with " transistor characteristic control terminal " is back of the body gate type thin film Transistor or MOS transistor, as shown in Figure 3 B.Subsidiary, at the picture according to the first comparative example In element circuit 10X, each transistor characteristic of sampling transistor 125 and driving transistor 121 controls Terminal is connected to ground potential points (minimum voltage used in image element circuit 10).Comparing according to second In the image element circuit 10Y of example, the transistor characteristic control terminal of sampling transistor 125 is connected to earth potential Point (minimum voltage used in image element circuit 10), but drive the transistor characteristic control of transistor 121 Terminal processed is connected to drive the source terminal of transistor 121.In the case of the second comparative example, worry reliable Property be adversely affected, this is because when turn off drive transistor 121 time (by by the second electromotive force V_{CC_L} It is applied to extinguishing (quenching) time of drain terminal), occur the drain terminal driving transistor 121 to become The reverse bias condition lower than base (base) electromotive force (back gate voltage).Although being not described in detail, but this It is due to the fact that when turning off driving transistor 121, drives the drain voltage of transistor in short-term In drop to the second electromotive force VCC_L, but when parasitic capacitance C of organic EL element 127_elAnd auxiliary Electric capacity 310(C_sub) electric discharge time, source electromotive force and base electromotive force certain time to be spent realize voltage decline.

On the other hand, first embodiment includes the transistor characteristic control with Characteristics Control sweep test 621 Part 620A processed, and first embodiment is configured to special from transistor Characteristics Control part 620A( Property control sweep test 621) " predetermined control electromotive force " be applied to the transistor of sampling transistor 125 Characteristics Control terminal.Subsidiary, in the first embodiment, as at the image element circuit according to the second comparative example In 10Y, the transistor characteristic control terminal of transistor 121 is driven to be connected to drive the source of transistor 121 Terminal.And, as in the image element circuit 10X according to the first comparative example, drive the crystalline substance of transistor 121 Body pipe Characteristics Control terminal may be connected to ground potential points.

As will be described in detail later, " predetermined control electromotive force " is the pulse for suppressing luminance shortage phenomenon The control voltage of form.Owing to luminance shortage phenomenon is relevant with signal write, so substantially utilizing use The Characteristics Control that the structure of the signal relevant with signal write controls part 620A as transistor characteristic is swept Retouch the structure of part 621.Such as, Characteristics Control sweep test 621 produces corresponding to transistor characteristic control The high/low scanning impulse of signal Vb processed, makes scanning impulse carry out level conversion, and then passes through spy Property control the output of scan line 621VB there is the transistor characteristic control signal of appropriate level Vb_H and Vb_L Vb。

" signal relevant with signal write " uses the signal shown in other embodiments to be described Canonical representation, but it is not limited to these signals.In other words, it is believed that the structure of first embodiment applies to The general construction of each " signal relevant with signal write ", but to be described other is implemented Example is the form of the object lesson of " signal relevant with signal write ".

[operation of image element circuit]

Figure 10 is for helping explain signal amplitude V by by-line system_inInformation write storage capacitor The sequential chart (perfect condition) of operation when 120, it is as about image element circuit 10(comparative example and first Each in embodiment) the example of driving timing.What Figure 10 was shown on axle common time writes scan line The potential change of 104WS, the potential change of power line 105DSL and the electricity of video signal cable 106HS Gesture changes.Figure 10 also illustrates the gate potential V driving transistor 121 abreast with these potential change_gWith Source electromotive force V_sChange.Basic, with the delay of a horizontal sweep period to every row write scan line 104WS and power line 105DSL performs similar driving.

The electricity of organic EL element 127 is flow through by the timing controlled of pulse (signal in such as Figure 10) The value of stream.In the timing example of Figure 10, by driven by power pulse DSL being arranged to the second electricity Gesture V_{CC_L}And after performing extinguishing and the initialization of node ND122, by by sampling transistor 125 It is arranged on open state to initialize node ND121, simultaneously by primary nodal point initialization voltage V_ofsIt is applied to Video signal cable 106HS, and in a state driven by power pulse DSL is arranged to the first electromotive force VCC_H, thus carries out threshold correction.Hereafter, sampling transistor 125 is arranged on off status, and By video signal V_sigIt is applied to video signal cable 106HS.In this state, sampling transistor 125 It is arranged on open state, thus is simultaneously written signal and carries out mobility correction.After write signal, Light emission is started when sampling transistor 125 is arranged on off status.Therefore by the phase contrast of pulse it is Mobility correction, threshold correction etc. control to drive.When driving display device 1A according to first embodiment In image element circuit 10A time, by transistor characteristic control signal Vb based on " relevant with signal write Signal " (mode associated with signal writing operation) pulsed drive (pulse-drive) sample crystal The backgate terminal of pipe 125.

This operation described in detail below, attention points to threshold correction and mobility correction.At pixel electricity In road 10, for driving timing, first sampling transistor 125 is in response to executing from writing scan line 104WS Add writes driving pulse WS and turns on, the video signal applied from video signal cable 106HS with sampling V_sigAnd by video signal V_sigIt is maintained in storage capacitor 120.Hereinafter, for the ease of introducing and reason Solve, except as otherwise noted, will be by by signal amplitude V_inInformation table be shown as write, be maintained at or adopt Sample concisely describes, for example, it is assumed that writing gain is 1(ideal value in storage capacitor 120). When writing gain less than 1, corresponding to signal amplitude V_inSize and with the information of multiplied by gains rather than Signal amplitude V_inItself, be maintained in storage capacitor 120.

For the driving timing of image element circuit 10, when by video signal V_sigSignal amplitude V_inInformation When writing storage capacitor 120, performing by-line and drive, from the angle of scanning continuously, it is simultaneously by a line Video signal transmission to the video signal cable 106HS of each row.Concrete, at the picture utilizing 2TR to construct Driving timing in element circuit 10 carries out, in the basic conception of threshold correction and mobility correction, first existing In the 1H period, video signal V_sigThere is reference potential (V based on timesharing_ofs) and signal potential (V_ofs+V_in).Especially, it is assumed that video signal V_sigAt reference potential (V_ofs) place, as invalid The period of period is the first half parts of a horizontal period, and video signal V_sigAt video electromotive force (V_sig=V_ofs+V_in) place, the second half parts that as period of effectual time are a horizontal period. When a horizontal period is divided into the first half parts and the second half parts, horizontal period typically by It is divided into the half of substantially equal period.But, this is dispensable.The second half parts can be longer than the first half portions Point, or contrary, the second half parts can be shorter than the first half parts.

Assume to be additionally operable to threshold correction and mobility correction for the driving pulse WS that writes of signal write, and And write driving pulse WS by twice activation in the 1H period and open sampling transistor 125.First Individual opening carries out threshold correction in (on) timing, and performs signal write in second Open Timer simultaneously Correct with mobility.Hereafter, transistor 121 is driven to receive from electricity at the first electromotive force (high potential side) The electric current of source line 105DSL, and, (right according to the signal potential being maintained in storage capacitor 120 Should be in the video signal V in effectual time_sigThe electromotive force of electromotive force) electric current I will be driven_dsIt is fed through organic EL element 127.Subsidiary, substitute twice activation in the 1H period and write driving pulse WS, Ke Yi While keeping the open state of sampling transistor 125, the electromotive force of video signal cable 106HS is arranged letter Number electromotive force (=V_ofs+V_in) in order to control the brightness in organic EL element 127.

Such as, at video signal V_sigInactive time period in, vertical driving section 103 output write driving arteries and veins Rush WS as control signal, be used for making sampling transistor 125 at power line 105DSL at the first electromotive force And video signal cable 106HS is at reference potential (V_ofs) period time in turn on, thus by correspondence In the threshold voltage V driving transistor 121_thVoltage be maintained at storage capacitor 120 in.This operation is real Existing threshold correction function.This threshold correction function can offset the threshold voltage V driving transistor 121_thShadow Ringing, this threshold voltage changes between image element circuit 10.

Vertical driving section 103 is preferably by sampled signal amplitude V_inBefore, in multiple horizontal period It is repeatedly carried out threshold correction operation, makes the threshold voltage V corresponding to driving transistor 121_thVoltage It is maintained at definitely in storage capacitor 120.Guarantee sufficiently long by threshold correction operation is performed a plurality of times Write the time.This makes to can ensure that the threshold voltage V that would correspond to drive transistor 121 in advance_thVoltage protect Hold in storage capacitor 120.

Keep corresponding to threshold voltage V_thVoltage for offset drive transistor 121 threshold voltage V_th.Therefore, even change between image element circuit 10 as the threshold voltage vt h driving transistor 121 Time, it is also possible to it is completely counterbalanced by the change of each image element circuit 10, thus it is (that is, aobvious to improve image conformity The uniformity of the luminosity on the whole screen of showing device).Especially, it is possible to prevent when signal potential is used The brightness flop occurred is tended to when low gray scale (gradation).

Preferably, vertical driving section 103 video signal V before threshold correction operates_sigInvalid time In Duan by power line 105DSL at the second electromotive force and video signal cable 106HS at reference potential (V_ofs) period time in activate write in driving pulse this example of WS(as H-level) and make sampling brilliant Body pipe 125 turns on, and subsequently will write driving heartbeat pulse WS be maintained at effectively (active) H While power line 105DSL is arranged to the first electromotive force.

Therefore, the second electromotive force V is reset at source terminal S_{CC_L}(electric discharge period C=secondary nodal point initializes Period) and drive the gate terminal G of transistor 121 to reset to basis reference electromotive force (V_ofs) (initialize Period D=primary nodal point initialization period) after, start threshold correction operation (threshold correction period E), This second electromotive force V_{CC_L}It is sufficiently below reference potential (V_ofs).This resetting gate electromotive force and the behaviour of source electromotive force Make the threshold correction operation that (initialization operation) makes it possible to reliably perform subsequently.Electric discharge period C and Initialization period D will be collectively known as the threshold correction preparation period (=pretreatment period), be used for initializing Drive the gate potential V of transistor 121_gWith source electromotive force V_s。

In threshold correction period E, the electromotive force of power line 105DSL the second electromotive force from low potential side V_{CC_L}The the first electromotive force V being converted on high potential side_{CC_H}, thus drive the source electromotive force V of transistor 121_s Begin to ramp up.Concrete, drive the gate terminal G of transistor 121 to be maintained at video signal V_sigBenchmark Electromotive force (V_ofs), and drain current flows is until driving the electromotive force V of the source terminal S of transistor 121_s The rear drive transistor 121 of rising is truncated.When driving transistor 121 to be truncated, drive transistor The source electromotive force Vs of 121 becomes " V_ofs-V_th”.In threshold correction period E, in order to allow leakage current only Flow through storage capacitor 120 side and (work as C_CS<<C_elTime) and stop drain current to flow to organic EL unit Part 127 side, arranges the electromotive force V of the public ground circuit cath of all pixels_cath, in order to block organic EL Element 127.

Due to by diode and parasitic capacitance C_elParallel circuit represent the equivalence of organic EL element 127 Circuit, if so " V_el≤V_cath+V_thEL" (if the leakage (leakage) of i.e. organic EL element 127 Electric current drives the electric current of transistor 121 much smaller than flowing through), drive the drain current I of transistor 121_dsQuilt For to storage electric capacity 120 and parasitic capacitance C_elCharging.As a result, the anode tap of organic EL element 127 The voltage V of sub-A_el(that is, the electromotive force of node ND122) rises in time.Then, as node ND122 Electromotive force (source electromotive force V_s) and voltage (the gate potential V of node ND121_gElectric potential difference between) is just Become threshold voltage V_thTime, drive transistor 121 to change to off status, drain current I from open state_dsStop Fluid stopping is moved, and the threshold correction period terminates.That is, after special time, transistor 121 is driven Gate source voltage V_gsUse threshold voltage V_th。

In this case, can only perform threshold correction to operate once.But, this is dispensable.Can Repetitive operation threshold correction repeatedly, wherein with horizontal period for processing the cycle.Such as, preferably, By a threshold correction, would correspond to threshold voltage V_thVoltage write storage capacitor 120, this is deposited Storage capacitor 120 is connected between the gate terminal G and source terminal S of driving transistor 121.But, threshold Value correction period E lasts till will write driving arteries and veins from by the moment writing driving pulse WS and arranging effective H Rush WS and return to the moment of invalid L.When this period of insufficient guarantee, this period is reaching corresponding In threshold voltage V_thVoltage before terminate.Threshold correction operation is preferably repeated several times solve this and ask Topic.The timing of the most not shown this threshold correction operation.

When threshold correction operation is performed a number of times, a horizontal period is the process week of threshold correction operation Phase, this is because performed initialization operation before threshold correction operates, this initialization operation is at a water At ordinary times the first half parts of section apply reference potential (V by video signal cable 106HS_ofs) and will Source electromotive force arranges the second electromotive force V_{CC_L}.The threshold correction period is necessarily shorter than a horizontal period.Therefore, Owing to storing the capacitance C of capacitor 120_CS, the second electromotive force V_{CC_L}Magnitude relationship and other factors, There may be situations below: in a short period of time of threshold correction operation, corresponding to threshold voltage V_th Precise voltage may not be entirely held in storage capacitor 120 in.Threshold correction is preferably performed a plurality of times Operation processes this situation.I.e., preferably by sampled signal amplitude V in storage capacitor 120_in In multiple horizontal period, repeat threshold correction operation before (signal write), would correspond to assuredly Drive the threshold voltage V of transistor 121_thVoltage be maintained at storage capacitor 120 in.

Image element circuit 10 also has mobility calibration function in addition to threshold correction function.Concrete, in order to It is in video signal V at video signal cable 106HS_sigEffectual time in signal potential (V_ofs+V_in) Being arranged in conducting state by sampling transistor 125 in period time at place, vertical driving section 103 is only The driving pulse of writing being applied to write scan line 104WS for the period shorter than above period time keeps For effectively (being H-level in the present example).In this short period of time, drive transistor 121 at signal Electromotive force (V_ofs+V_in) be applied to drive transistor 121 control input terminal state in, to organic Parasitic capacitance C of EL element 127_elCharge with storage capacitor 120.When corresponding to signal amplitude V_in Information be maintained at storage capacitor 120 in time, by suitably arrange write having of driving pulse WS The effect period (this period is also sampling periods and mobility correction period), transistor can be driven simultaneously The correction of the mobility [mu] of 121.By horizontal driving section 106 by signal potential (V_ofs+V_in) actual It is applied to video signal cable 106HS and the period writing driving pulse WS and being set to effective H is set It is set to signal amplitude V_inWrite the period of storage capacitor 120 (when this period will also referred to as sample Section).

Concrete, in the driving timing of image element circuit 10, at power line 105DSL in high potential side First electromotive force V_{CC_H}And video signal V_sig(at signal amplitude V in effectual time_inPeriod in) Period in, activate write driving pulse WS.I.e. as a result, define mobility timing by a scope Section (and sampling periods), in this range, the electromotive force of video signal cable 106HS is video signal V_sig Effectual time in signal potential (V_ofs+V_in) period in time width with write driving pulse WS's Effectual time overlaps each other.Concrete, it is set to owing to writing the effectual time width of driving pulse WS Narrower, in order to be contained in video signal cable 106HS and be in the time width of signal potential, so moving Shifting rate is determined by writing driving pulse WS correction time.More accurately, (and adopt mobility correction time The sample period) it is to rise and sampling transistor 125 opens (turn on) to together from writing driving pulse WS One writes driving pulse WS declines and sampling transistor 125 turns off time of (turn off).

Concrete, in sampling periods, sampling transistor 125 is arranged in conducting (opening) state, its The gate potential V of middle driving transistor 121_gAt signal potential (V_ofs+V_in).Therefore, writing and migrating In rate correction period H, drive electric current I_dsIt is fixed on signal electricity at the gate terminal G driving transistor 121 Gesture (V_ofs+V_in) state in flow through driving transistor 121.Signal amplitude V_inInformation to be added to drive The threshold voltage V of dynamic transistor 121_thOn mode keep.As a result, the threshold value electricity of transistor 121 is driven Pressure V_thChange be always eliminated, it means that carried out threshold correction.As the result of threshold correction, The gate source voltage V kept by storage capacitor 120_gsIt is " V_sig+V_th”=“V_in+V_th”.It addition, Sampling periods carries out mobility correction simultaneously.Therefore sampling periods be also mobility correction the period (write and Mobility correction period H).

Made V at that time_thELFor the threshold voltage of organic EL element 127, carry out " V_ofs-V_th＜ V_thEL" When arranging, organic EL element 127 is arranged in reverse biased (reverse-biased) state and has Machine EL element 127 is the state of blocking (high impedance status).Therefore, organic EL element 127 is not launched Light, and present simple capacitance characteristic rather than diode characteristic.Therefore, driving transistor 121 is flow through Drain current (drive electric current I_ds) it is written to electric capacity " C=C_CS+C_el", this electric capacity " C=C_CS+C_el” By the electric capacity C by storage capacitor 120_CSParasitic capacitance (equivalent capacity) with organic EL element 127 C_elElectric capacity C_elCombine and obtain.Therefore, the drain current of transistor 121 is driven to flow to organic EL unit Parasitic capacitance C of part 127_elIn, and therefore start to charge up.As a result, the source electromotive force of transistor 121 is driven V_sRise.

In the sequential chart of Figure 10, this rising Δ V represents.As the result of threshold correction, this rising (i.e. as the potential correction value Δ V of mobility correction parameter) is by from being maintained in storage capacitor 120 Gate source voltage " V_gs=V_in+V_thDeduct in ", and " V_gs=V_in+V_th-Δ V ", it means that apply negative Feedback.The source electromotive force Vs driving transistor 121 is now by from gate potential V_g(=V_inGuarantor is deducted in) Hold the voltage " V in storage capacitor_gs=V_in+V_th-Δ V " and the value "-V that obtains_th+ΔV”。

Therefore, in the driving timing of image element circuit 10, writing with in mobility correction period H, holding Row signal amplitude V_inSampling and for correcting the degenerative amount of Δ V(or the mobility of mobility [mu] Correction parameter) adjustment.Write sweep test 104 adjustable to write and the time width of mobility correction period H Degree.Therefore, it can optimize and drive electric current I_dsDegenerative amount.

Potential correction value Δ V is I_ds·t/C_el.Even if when due to the mobility [mu] in each image element circuit 10 Change and cause drive electric current I_dsDuring change, also obtain corresponding to the driving in each image element circuit 10 Electric current I_dsPotential correction value Δ V.Therefore, the change of the mobility [mu] in each image element circuit 10 can quilt Correction.Concrete, as signal amplitude V_inTime fixing, the mobility [mu] driving transistor 121 is the biggest, electricity The absolute value of gesture correction value delta V is the biggest.In other words, mobility [mu] is the biggest, and value Δ V is the biggest for potential correction, Thus the change of the mobility [mu] in each image element circuit 10 can be removed.

Image element circuit 10 also has bootstrapping function.Concrete, at signal amplitude V_inInformation be maintained at In stage in storage capacitor 120, write sweep test 104 cancellation and write driving pulse WS to writing scanning The applying of line 104WS (that is, will write driving pulse WS invalid L(is set low)), thus will sampling Transistor 125 is arranged on nonconducting state, and therefore the gate terminal G of transistor 121 will be driven from regarding Frequently holding wire 106HS electrically disconnects (emission period I).Before emission period I, horizontal driving section The electromotive force of video signal cable 106HS is returned to reference potential (V at suitable subsequent point in time by 106_ofs).

The luminance of organic EL element 127 lasts till that (m+m '-1) is till the horizontal sweep period. This terminates formation (n, m) light emission operation of the organic EL element 127 of sub-pixel.Hereafter, enter To next frame (or field), again repeat threshold correction preparatory function, threshold correction operation, mobility school Just operating and light emission operation.

In emission period I, the gate terminal G and video signal cable 106HS of transistor 121 is driven to disconnect. Owing to eliminating signal potential (V_ofs+V_in) it is applied to drive the gate terminal G of transistor 121, so Drive the gate potential V of transistor 121_gBecome able to rise.Storage capacitor 120 is connected to drive crystal Between the gate terminal G and source terminal S of pipe 121.Bootstrapping behaviour is performed by the effect of storage capacitor 120 Make.Assume that bootstrapping gain is 1(ideal value), then drive the gate potential V of transistor 121_gWith driving crystal The source electromotive force V of pipe 121_sThe association of change operation ground, thus gate source voltage V_gsCan keep constant.Now, Flow through the driving electric current I driving transistor 121_dsFlow to organic EL element 127, and organic EL element The anode potential of 127 is according to driving electric current I_dsAnd rise.Assume that this ascending amount is V_el.Along with source voltage The rising of Vs, the final reverse bias condition eliminating organic EL element 127.Therefore, organic EL unit Part 127 is actually with the driving electric current I being flowed in organic EL element 127_dsStart to launch light.

By by " V_sig+V_th-Δ V " or " V_in+V_th-Δ V " it is updated to aforesaid expression transistor characteristic Formula (1) in, can will drive electric current I_dsWith gate source voltage V_gsRelational representation be formula (5A) Or formula (5B) (two formula will be collectively referred to as formula (5)).

I_ds=k·μ·(V_sig–V_ofs–ΔV)² (5A)

I_ds=k·μ·(V_in–V_ofs–ΔV)² (5B)

Formula (5) display threshold voltage V_thItem be eliminated, and be applied to organic EL element 127 Driving electric current Ids be not dependent on drive transistor 121 threshold voltage V_th.I.e., such as work as V_ofsIf Put when 0 volt, flow through the electric current I of organic EL element 127_dsWith by from control organic EL element The video signal V of the brightness of 127_sigValue in deduct secondary nodal point ND2(drive transistor 121 source Terminal) the potential correction value Δ V at place and the value that obtains square proportional, potential correction Δ V-value is originated In the mobility [mu] driving transistor 121.In other words, the electric current I of organic EL element 127 is flow through_dsNo Depend on the threshold voltage V of organic EL element 127_thELOr drive the threshold voltage V of transistor 121_th。 That is, organic EL element 127 light quantity (brightness) launched is not by the threshold value electricity of organic EL element 127 Pressure V_thELOr drive the threshold voltage V of transistor 121_thImpact.(n, m) organic EL unit The brightness of part 127 corresponds to electric current I_dsValue.

It addition, the transistor 121 that drives of high mobility μ has a bigger potential correction value Δ V, and because of This has the gate source voltage V of smaller value_gs.Therefore, even if when the mobility [mu] in formula (5) is bigger Value time, (V_sig-V_ofs-Δ V)²Value the least, thus recoverable drain current I_ds.That is, even if existing Drive transistor 121 mobility [mu] different from each other in the case of, as video signal V_sigWhen being worth identical, Drain current I_dsThe most essentially identical.As a result, flow through organic EL element 127 and control organic EL element The electric current I of the brightness of 127_dsHomogenized.That is, the brightness flop of organic EL element 127 can be corrected, This change is caused by the change (and change of k) of mobility [mu].

It addition, storage capacitor 120 be connected to drive transistor 121 gate terminal G and source terminal S it Between, and perform bootstrapping operation when emission period starts due to the effect of storage capacitor 120.Drive The gate potential V of dynamic transistor 121_gWith source electromotive force V_sRise, and simultaneously drive the gate-source of transistor 121 Voltage " V_gs=V_in+V_th-Δ V " keep constant.As the source electromotive force V driving transistor 121_sBecome “-V_th+ΔV+V_el" time, gate potential Vg becomes " V_in+V_el”.Now, owing to driving transistor 121 Gate source voltage V_gsConstant, so driving transistor 121 that (constant current is driven electric current I_ds) feed By organic EL element 127.As a result, the electromotive force (=joint of the anode terminal A of organic EL element 127 The electromotive force of some ND122) rise to a voltage so that as the driving electric current I in saturation_dsElectricity Stream can flow through organic EL element 127.

The long fluorescent lifetime of organic EL element 127 changes the I-V characteristic of organic EL element 127.Therefore, The electromotive force of node ND122 changes over time.But, even if when due to organic EL element The long-term degradation of 127 and when causing the anode potential change of this organic EL element 127, store capacitor The 120 gate source voltage Vgs kept also are constantly maintained at " V_in+V_th-ΔV”.Transistor 121 is driven to make Operate for constant-current source.Therefore, though when organic EL element 127 I-V characteristic over time and Change, and drive the source electromotive force V of transistor 121_sDuring respective change, owing to driving transistor 121 Gate source voltage V_gsConstant (≈ V is kept by storage capacitor 120_in+V_th-Δ V), therefore flow through organic EL The electric current of element 127 is the most constant, and the luminosity of therefore organic EL element 127 also keeps constant. It practice, bootstrapping gain is less than " 1 ".Therefore, gate source voltage V_gsFrom " V_in+V_th-Δ V " reduce, But still keep the gate source voltage V corresponding to gain of booting_gs。

As described above, when design driven timing, image element circuit 10 automatically forms threshold correction electricity Road and mobility correcting circuit.Concrete, in order to stop the characteristic variations driving transistor 121 (originally to be shown Example is threshold voltage V_thChange with carrier mobility μ) to driving electric current I_dsImpact, pixel Circuit 10 is used as to drive signal homogenization circuit, for by corrected threshold voltage V_thAnd carrier mobility The impact of rate μ and keep driving current constant.Not only can perform bootstrapping operation, can also carry out threshold correction Operation and mobility correct operation.Therefore, by corresponding to threshold voltage V_thWith correct for mobility The gate source voltage V that the Voltage Cortrol of potential correction value Δ V is kept by bootstrapping operation_gs.Therefore, organic The luminosity of EL element 127 is not driven the threshold voltage V of transistor 121_thOr mobility [mu] Change impact, do not affected by the long-term degradation of organic EL element 127.As a result, display device 1 Can correspond to incoming video signal V_sig(signal amplitude V_in) stable gray scale show, and because of This provides the image of high image quality.

It addition, the source follower circuit of transistor 121 can be driven to form image element circuit by using n-channel-type 10.Therefore, even if organic EL of the anode having in present case and cathode electrode ought be used as former state During element 127, image element circuit 10 also can drive organic EL element 127.It addition, image element circuit 10 can Formed merely with n-channel transistor, including driving transistor 121, driving transistor 121 outer part The sampling transistor 125 etc. divided.Therefore, the reduction of transistor manufacturing cost can be obtained.

[there is the reason of luminance shortage phenomenon]

When sampling periods and mobility calibrate the signal writing operation in the period, how to use larger quantities And higher fidelity (fidelity) (having linear) would correspond to signal potential V (magnitude)_in Information write storage capacitor 120 in extremely important." larger quantities " is write gain G by so-called_inFixed Justice.In order to about video signal V_sigSignal potential V_inGuarantee brightness efficiently, drive electric current I_ds Along with the gate potential V driving transistor 121_gRising and flow and source electromotive force V_sTime in write (the low source electromotive force V of transistor 121 is i.e. driven in the write time in the case of not rising_sIn the case of), Preferably by electric capacity C_CSStorage capacitor 120 voltage and the video signal V that keep_sigRatio (write gain G_in) be configured to the biggest.Use the electric capacity C of storage capacitor 120_CS, driving transistor 121 Parasitic capacitance C121 formed at gate terminal G_gsElectric capacity C_gs, and the parasitism of organic EL element 127 Electric capacity C_el, can by this case write gain G_inIt is expressed as

G_in=C2/(C1+C2)=(C_CS+C_gs)/{ (C_CS+C_gs)+C_el}

When considering auxiliary capacitor 310, by C_elBecome " C_el+C_sub" be sufficient for.

Parasitic capacitance C121_gsElectric capacity C_gsIt is believed that less than the electric capacity C of storage capacitor 120_CSWith organic Parasitic capacitance C of EL element 127_el.Therefore, when parasitic capacitance C of organic EL element 127_elFully Electric capacity C more than storage capacitor 120_CSTime, or in other words, when being added to drive transistor 121 Capacitance between gate terminal G and source terminal S is (in this case for the electric capacity C of storage capacitor 120_CS) Maybe when being added to drive the source terminal S(i.e. anode terminal of organic EL element 127 of transistor 121 during reduction A) and the cathode terminal K of cathode circuit cath(organic EL element 127) between capacitance (at this It situation is parasitic capacitance C of organic EL element 127_el) increase time, write gain G_inUnlimited near " 1 ". Therefore, closer to signal potential V_inThe information of voltage of size can be written to store capacitor 120.

On the other hand, it has been found that " higher fidelity (having linear) " is needed to consider back-gate effect (also referred to as substrate bias effect (substrate bias effect)).Concrete, when use has backgate effect The field-effect transistor answered is as write transistor TR_WTime, there is following phenomenon: even if when inputting high video When signal level is to obtain high brightness, it is also possible to the brightness corresponding to incoming video signal level can not be obtained. Such as assume to use MOS transistor.Generally, in image element circuit 10, the base electromotive force of MOS transistor (base voltage) (back gate potential) is disposed substantially in emission state the minimum voltage used.Such as, as In first comparative example of Fig. 4 and Fig. 5, apply the minimum voltage (earth potential) as fixed potential to base Electromotive force.In this case, necessary luminosity is the biggest, and gate potential and source electromotive force need the highest, and Base-source voltage V between source terminal and cardinal extremity (backgate terminal)_bsIncrease the most.But, this In situation, along with base-source voltage V_bsIncrease, due to the threshold value of substrate bias effect sampling transistor 125 Voltage V_thIncrease, and hence in so that write is difficult, and work on the direction of suppression brightness. Therefore luminance shortage phenomenon occurs.Luminance shortage phenomenon is different according to gray scale (gradation), this meaning Taste has γ characteristic (linearly losing) for each gray scale.In the case of colour shows, worry tone Skew.In order to eliminate luminance shortage phenomenon, need to increase further the gate source voltage of sampling transistor 125 V_gs.As a result, video signal V_sigVoltage need be set higher.

[as the method for the countermeasure measuring luminance shortage phenomenon]

The present embodiment is by by transistor characteristic control signal based on " signal relevant with signal write " Vb is applied to the transistor characteristic control terminal of sampling transistor 125, eliminates and is caused by back-gate effect Luminance shortage phenomenon, and thus improve transistor characteristic when signal writes." improvement transistor characteristic " Refer to such as improve write capability, and reduce threshold voltage V_th。

Figure 11 and 12 is to aid in explaining the former of the countermeasure for the luminance shortage phenomenon caused by back-gate effect The figure of reason.Figure 11 is to aid in explaining transistor characteristic (V_gs-I_dsCharacteristic) dependent to substrate electromotive force Figure.Figure 12 is to aid in explaining the sequential chart of the method driving the image element circuit according to first embodiment, notes Power points to transistor characteristic control signal Vb.

As it is known, due to back-gate effect, back of the body gate type thin film transistor or the transistor of MOS transistor Characteristic is different.Such as, usually, MOS transistor be generally taken as there is bipolar transistor three Terminal device.But, more accurately, MOS transistor also should be taken as four-terminal device, this is because Form source region and the substrate in drain region or trap should be taken as control terminal (transistor characteristic control terminal). When transistor characteristic control signal Vb(is also referred to as back gate voltage, substrate electromotive force or base electromotive force) apply To time between source terminal and transistor characteristic control terminal (such as substrate (also known as body)), can control Transistor characteristic.Back gate voltage is typically applied to as negative voltage, thus diode is in the state of blocking.Such as, When applying back gate voltage, tightly it is located immediately at the depletion layer under source and leakage raceway groove and is changed, as in two poles As in pipe, and the electromotive force of semiconductor surface changes.Therefore, according to whether be applied with back gate voltage, Change the electric charge in depletion layer.As shown in Figure 11, transistor characteristic (V_gs-I_dsCharacteristic) it is changed. Therefore, threshold voltage V_thIt is changed.It is known that when considering back-gate effect, threshold voltage V_thAbout to carry on the back The speed of 1/2 power of gate voltage increases.Subsidiary, although in simple theory, threshold voltage V_th Increase with the speed of 1/2 power of about back gate voltage, even if generally this increase being regarded as linearly increasing, real In trampling, also there is no problem.

As shown in Figure 11, along with substrate electromotive force (that is, transistor characteristic control signal Vb) rises, Threshold value declines, such that it is able to promote by the sampling transistor 125 write to signal voltage.That is, as In Figure 12, transistor characteristic control signal Vb based on " signal relevant with signal write " is sufficient to Enough at least in time for writing signal (specially adjacent after write starts certain (certain) period) Reduce the threshold voltage V of sampling transistor 125_th." adjacent certain period after write starts " no Need to be that video signal writes whole period (sampling periods in first embodiment and the mobility processing step The correction period), and refer to its threshold voltage V that be enough to change sampling transistor 125_th, in order to from opening The threshold voltage V of sampling transistor 125 is reduced during this certain period begun_th." certain period " be Voltage corresponding to the amplitude of video signal is written to store the just foot of the period before capacitor 120 substantially Enough.

In each image element circuit 10A, transistor characteristic controls part 620A and is configured to arrange sampling crystalline substance Transistor characteristic control signal Vb of body pipe 125.When during the certain period starting from signal write When improving transistor characteristic control signal Vb of sampling transistor 125, threshold voltage V can be made_thIt is lower, Such that it is able to promote by the sampling transistor 125 write to signal voltage.Input high video level To obtain high brightness, and by the way of associating with the input operation with high video level similarly Improve transistor characteristic control signal Vb for sampling transistor 125, change threshold voltage V_th.From And can suppress or eliminate luminance shortage phenomenon.Structure described above can eliminate be difficult to produce highlighted Degree (write difficulty) or the problem needing to arrange higher signal voltage.

[the second embodiment]

Figure 13 and 14 is to illustrate the image element circuit 10B according to the second embodiment and include this image element circuit The figure of the form of the display device of 10B.Pixel array portion 102 has according to the second embodiment The display device of image element circuit 10B will be referred to as display device 1B according to the second embodiment.Figure 13 shows Go out (each pixel) essential structure.Figure 14 illustrates specific configuration (whole display device).Figure 15 Being to aid in explaining the sequential chart of the operation of the second embodiment, attention points to transistor characteristic control signal Vb.

As shown in figure 13 and figure 14, the second embodiment has transistor in each image element circuit 10B Characteristics Control part 620B.Transistor characteristic controls part 620B and has capacity cell 622, this electric capacity Element 622 is connected to transistor characteristic control terminal (backgate terminal) and the control of sampling transistor 125 Between input terminal processed (gate terminal).Characteristics Control sweep test 621 is not necessarily.Subsidiary, In fig. 13 by resistive element R_BGRepresent the line resistance of the backgate of sampling transistor 125.Transistor Characteristics Control part 620B may also include and is applied to transistor characteristic control for adjustment by capacity cell 622 The time constant adjustment member 624 of the time constant of the signal of terminal processed, but time constant adjustment member 624 not necessarily.As an example, time constant adjustment member 624 has resistive element 625, this electricity Resistance element 625 is connected to the transistor characteristic control terminal of sampling transistor 125 and for applying transistor Between the circuit of characteristic control signal Vb.In fig. 13, resistive element 625 is arranged on capacity cell 622 And between the backgate terminal of sampling transistor 125.But, resistive element 625 may be provided at capacity cell Between 622 and the gate terminal of sampling transistor 125.

About the transistor characteristic control how producing the luminance shortage phenomenon caused for suppression by back-gate effect Signal Vb processed, controls part 620A according to the transistor characteristic of first embodiment and uses " with signal write Relevant signal ", and it be also possible to use arbitrary signal, as long as the signal relevant with signal write is used i.e. Can.On the other hand, the second embodiment use writes arteries and veins for what the ON/OFF performing sampling transistor 125 controlled Rush the WS object lesson as " signal relevant with signal write ".In a second embodiment, electric capacity Element 622 is added between the backgate of sampling transistor 125 and grid line (writing scan line 104WS), from And coupling (coupling) voltage writing a signal to the rising edge of the write pulse WS of time is input to base electricity Gesture, and thus promote by the sampling transistor 125 write to signal voltage.

As shown in Figure 15, when write pulse WS is coupled to backgate terminal by capacity cell 622, right In from sampling periods and mobility correct the period start certain period, transistor characteristic control signal Vb Can increase.Therefore, the threshold voltage V of sampling transistor 125 is changed_thTo become lower, such that it is able to promote Enter by the sampling transistor 125 write to signal voltage.Subsidiary, due to writing of time for writing signal The coupling of the trailing edge of pulse WS, for the certain period starting from trailing edge, is used for crystal of sampling Transistor characteristic control signal Vb of pipe 125 declines.But, this does not comes into question.It addition, it is different 3rd embodiment to be described, for from initialize node ND121(primary nodal point) period The certain period started, the transistor characteristic control signal for sampling transistor 125 increases.But, This does not comes into question.

Subsidiary, the base electromotive force of sampling transistor 125 is fixed potential, and coupled voltages is not ideally It is input to base voltage.It is additionally, since line resistance (the resistive element R that there are in fact backgate_BG), institute To be connected to the backgate terminal as transistor characteristic control terminal and control input when resistive element 622 Time between son, coupled voltages can be imported into backgate terminal, as in a second embodiment.

But, line resistance (the resistive element R of backgate_BG) there is less resistance value, and may There is the situation by the coupling of capacity cell 622 with less impact.That is, by capacity cell 622 With line resistance (=resistive element R_BG) time constant that limits is less, and coupled voltages application time Shorter.When increasing transistor characteristic control signal Vb at sampling periods and mobility correction period when starting Period expectation when being lengthened to a certain degree, preferably by the transistor characteristic at sampling transistor 125 Control terminal and being used for applies to provide between transistor characteristic control signal Vb circuit resistive element 625 Form time constant adjustment member 624.Due to the insertion of resistive element 625, resistive element 625 He Resistive element R_BGBetween divide write pulse WS voltage.However, it is possible to improve by capacity cell 622 Line resistance=resistive element R with resistive element 625(and backgate_BG) time constant that limits.Cause This, can extend and increase transistor characteristic control signal Vb at sampling periods and mobility correction period when starting Period.

[the 3rd embodiment]

Figure 16 and 17 is to illustrate the image element circuit 10C according to the 3rd embodiment and include image element circuit 10C The figure of form of display device.There is in pixel array portion 102 pixel according to the 3rd embodiment The display device of circuit 10C will be referred to as display device 1C according to the 3rd embodiment.Figure 16 illustrates (one Individual pixel) essential structure.Figure 17 illustrates specific configuration (whole display device).Figure 18 illustrates help Explaining the sequential chart of the operation of the 3rd embodiment, attention points to transistor characteristic control signal Vb.

As shown in Figure 16 and Figure 17, the 3rd embodiment has transistor in each image element circuit 10C Characteristics Control part 620C.Transistor characteristic controls part 620C and has capacity cell 632, this electric capacity Element 632 is connected to transistor characteristic control terminal (backgate terminal) and the conduct of sampling transistor 125 Between the video signal cable 106HS of video signal cable DTL.Characteristics Control sweep test 621 is not must Must.Subsidiary, in figure 16 by resistive element R_BGRepresent the line of the backgate of sampling transistor 125 Road resistance.Transistor characteristic control part 620C be may also include and applied by capacity cell 632 for adjustment To the time constant adjustment member 634 of time constant of the signal of transistor characteristic control terminal, but time Between constant adjustment member 634 not necessarily.As an example, time constant adjustment member 634 has electricity Resistance element 635, this resistive element 635 is connected to the transistor characteristic control terminal of sampling transistor 125 And between the circuit applying transistor characteristic control signal Vb.In figure 16, resistive element 635 It is arranged between the backgate terminal of capacity cell 632 and sampling transistor 125.But, resistive element 635 May be provided between capacity cell 632 and video signal cable 106HS.

3rd embodiment has the structure similar with the second embodiment, the differ in that: the 3rd is real Execute example to be regarded by the backgate and video signal cable DTL(that capacity cell 632 is added to sampling transistor 125 Frequently holding wire 106HS) between, and video signal V when writing a signal to_sigThe coupled voltages of rising edge It is input to base electromotive force, thus promotes by the sampling transistor 125 write to signal voltage.

As shown in Figure 18, it is coupled to by capacity cell 632 when the rising edge of the electromotive force of video signal cable During backgate terminal, for from sampling periods and mobility correct the period start certain period, crystal Pipe characteristic control signal Vb can increase.Therefore, the threshold voltage V of sampling transistor 125_thChange to become Lower, it is possible to promote by the sampling transistor 125 write to signal voltage.

Subsidiary, such as the second embodiment, also as in the 3rd embodiment, it is contemplated that the line resistance (electricity of backgate Resistance element R_BG) resistance value less, it is possible to provide the time similar to time constant adjustment member 624 is normal Number adjustment member 634 extends the beginning increase transistor spy correcting the period at sampling periods and mobility The period of property control signal Vb is to a certain extent.

In a second embodiment, constant transistor characteristic control signal Vb is applied to sampling transistor The backgate terminal of 125, and unrelated with the amplitude of video signal.In the third embodiment, have corresponding to Transistor characteristic control signal Vb of the size of the amplitude of video signal is applied to sampling transistor 125 Backgate terminal.That is, back-gate effect the luminance shortage phenomenon caused is according to video signal V_sigAnd different, And the 3rd embodiment can control the transistor characteristic in each image element circuit 10B when reflecting these difference Control terminal.

[the 4th embodiment]

Figure 19 and 20 is to illustrate the image element circuit 10D according to the 4th embodiment and include this image element circuit The figure of the form of the display device of 10D.Pixel array portion 102 has according to the 4th embodiment The display device of image element circuit 10D will be referred to as display device 1D according to the 4th embodiment.Figure 19 shows Go out (pixel) essential structure.Figure 20 illustrates specific configuration (whole display device).Figure 21 is Helping explain the sequential chart of the operation of the 4th embodiment, attention points to transistor characteristic control signal Vb.

As shown in Figure 19 and Figure 20, the 4th embodiment has transistor in each image element circuit 10D Characteristics Control part 620D.Transistor characteristic controls part 620D and has buffer (buffer) 642, This buffer 642 be connected to sampling transistor 125 transistor characteristic control terminal (backgate terminal) and Between control input terminal (gate terminal).Characteristics Control sweep test 621 is not necessarily.Subsidiary, In Figure 19, by resistive element R_BGRepresent the line resistance of the backgate terminal of sampling transistor 125. Transistor characteristic controls part 620D and may also include amplitude adjustment member 644, this amplitude adjustment member 644 For adjusting transistor characteristic control signal Vb being applied to transistor characteristic control terminal, but amplitude is adjusted It is not essential for for whole point 644.As an example, amplitude adjustment member 644 has resistive element 645, This resistive element 645 is connected to transistor characteristic control terminal and the buffer 642 of sampling transistor 125 Between.Transistor characteristic controls part 620D and may also include pulse width adjustment member 646, this pulse width Degree adjustment member 646 is for adjusting the transistor control signal Vb being applied to transistor characteristic control terminal Pulse width, but pulse width adjustment member 646 is not essential for.As an example, pulse Width adjustment loop 646 has differential (differentiating) circuit 647, for by buffer 642 Write pulse WS differential on input side.Be enough to form peaker by resistive element and capacity cell 647。

4th embodiment and the second embodiment similarity are to use the write pulse WS of time for writing signal. But, the 4th embodiment is with the difference of the second embodiment: the 4th embodiment is essentially by buffering Device 642 rather than coupled by the voltage of capacity cell, is input to sampling transistor 125 by write pulse WS Base electromotive force, thus promote by the sampling transistor 125 write to signal voltage.Insertion amplitude adjusts Part 644(resistive element 645) promote that the transistor being applied to the backgate terminal of sampling transistor 125 is special The adjustment of the size of property control signal Vb, as shown in figure 21.Insert pulse width adjustment member 646(micro- Parallel circuit 647) promote to be applied to the transistor control signal Vb of the backgate terminal of sampling transistor 125 The adjustment of pulse width Δ T, as shown in Figure 21.4th embodiment has than the second embodiment or The circuit structure that three embodiments are more complicated, but promote the backgate end being applied to sampling transistor 125 The size of transistor characteristic control signal Vb of son and the adjustment of application time.

[the 5th embodiment]

Figure 22 A to 22E is to aid in explaining the figure of the 5th embodiment.5th embodiment is to include display device The example of electronic installation, this display device applications is for suppressing or eliminating described above by carrying on the back The technology of the luminance shortage phenomenon that matrix effect causes.The place of the suppression display inhomogeneities according to the present embodiment Reason is applicable to display device, is included in the current drive-type display element that various electronic installation uses, this electricity Sub-device such as game machine, e-book, electronic dictionary, mobile phone etc..

Such as, Figure 22 A shows that electronic installation 700 is to use showing of the example as image display device Show the axonometric chart of the example of outward appearance in the case of the television set of module 704:.Television set 702 has setting Display module 704 in the front surface of the front panel 703 supported by pedestal 706, and at display table There is on face filtering glass 705.Figure 22 B is to illustrate the situation that electronic installation 700 is digital camera 712 In the figure of example of outward appearance.Digital camera 712 includes display module 714, controls switch 716 and fast Door button 717 etc..Figure 22 C illustrate electronic installation 700 be in the case of video camera 722 outside The figure of the example seen.Video camera 722 has the one-tenth for being imaged on the object before main body 723 As lens 725, and also include display module 724, for obtaining the beginning/shutdown switch 726 of image Deng.Figure 22 D be electronic installation 700 be the figure of the outward appearance example in the case of computer 732.Computer 732 include downside shell 733a, upside shell 733b, display module 734, IP Camera 735, keyboard 736 etc..Figure 22 E is to illustrate that electronic installation 700 is the outward appearance example in the case of portable phone 742 Figure.Portable phone 742 is folded form.Portable phone 742 include upside shell 743a, downside shell 743b, For hinge in display module 744a, sub-display 744b, photographic head 745, coupling part this example of 746( Chain part), image lamp 747 etc..

By using the display device according to the present embodiment to manufacture display module 704, display module 714, show Show module 724, display module 734, display module 744a and sub-display 744b.Therefore, each Electronic installation 700 be possible not only to correct by drive the threshold voltage of transistor and mobility change (and The change of k) and the brightness flop that causes, it is also possible to suppress or eliminate the brightness caused by back-gate effect Not foot phenomenon, and can therefore realize the display of high image quality.

Below the embodiment in this specification has been used to describe the technology disclosed in this specification.But, The technical scope of the content described in claim is not limited to the scope described in preceding embodiment.Can be to front The embodiment in face does various changes and modifications, without departing from the spirit of technology disclosed in this specification, And the form obtained by increasing this changes and improvements is also contained in the technology disclosed in this specification Technical scope.Embodiment above is not limited to relate to the technology of claim, and is not in embodiment The combination of all features described is all that the problem solving to be covered by the technology disclosed in this specification is musted Must.Embodiment above includes the technology in each stage, and by combining multiple disclosure suitably Detailing requiments can extract various technology.Even if when the possessive construction disclosed in the present embodiment requires When omitting some detailing requiments, the structure omitting the generation of some detailing requiments also can be extracted as in this specification Disclosed technology, as long as obtaining the effect of the problem corresponding to being covered by the technology disclosed in this specification ?.

Such as, about the luminance shortage phenomenon that caused by back-gate effect of elimination, it is possible to with would correspond to The driving voltage of video signal is write the mode processing operation association of storage capacitor and is controlled write transistor Characteristic is sufficient for, and it can be deployed in various structure, as long as can with the driving that would correspond to video signal The mode of the process operation association that voltage writes storage capacitor controls the characteristic of write transistor.For The component providing this is included in image element circuit not necessarily, and can be by by being arranged on picture The Characteristics Control sweep test 621 in control part 109(the example above outside element circuit) design picture The timing (difference with reference between first embodiment and the second to the 4th EXAMPLE Example) of element circuit 10 This offer is provided.

Selectively, do not providing independent Characteristics Control sweep test 621 in the outside of image element circuit 10, Can exist constructed as below: this structure uses the driving arteries and veins exported by another sweep test by logic circuit Punching produces the high/low scanning impulse corresponding to transistor characteristic control signal Vb, makes scanning impulse carry out Level conversion, and then output has appropriate level Vb_{_H}And Vb_{_L}Transistor characteristic control signal Vb。

It addition, in embodiment above and example, threshold voltage can be controlled when write transistor has During transistor control terminals (such as backgate terminal etc.), transistor characteristic control terminal for with by right The mode processing operation association of storage capacitor should be write in the driving voltage of video signal, control to write crystalline substance The characteristic of body pipe.But, this is only example, and this technology is not limited to use transistor characteristic to control end Son performs the structure controlled, as long as " certain period adjacent after writing beginning ", write transistor Write capability increases.Self-evident, can select and supplement structure, such as n-raceway groove in supplementary structure Transistor AND gate p-channel transistor exchanges, and the polarity of multiple electric power and signal inverts accordingly.

Explanation based on embodiment above, the technology relating to claim is example, and such as extracts Techniques below.This technology is listed below.

[supplementary notes 1]

A kind of image element circuit includes:

Display part；

Storage capacitor；

Write transistor, writes described storage capacitor for would correspond to the driving voltage of video signal；With And

Drive transistor, be used for, based on the driving voltage writing described storage capacitor, driving described display Part；

Wherein can be to write described storage capacitor with the driving voltage that would correspond to described video signal Process the mode of operation association, control the characteristic of described write transistor.

[supplementary notes 2]

According to the image element circuit described in supplementary notes 1, also include:

Characteristics Control part, it is configured to write institute with the driving voltage that would correspond to described video signal State the mode processing operation association of storage capacitor, control the characteristic of described write transistor.

[supplementary notes 3]

According to the image element circuit described in supplementary notes 1 or 2,

The process of described storage capacitor is wherein write at the driving voltage that would correspond to described video signal In period, increase the write capability of described write transistor.

[supplementary notes 4]

According to the image element circuit described in supplementary notes 3,

The process of described storage capacitor is wherein write with the driving voltage that would correspond to described video signal The write capability of described write transistor is increased while beginning.

[supplementary notes 5]

According to the image element circuit described in supplementary notes 3,

The process of described storage capacitor is wherein write with the driving voltage that would correspond to described video signal The threshold voltage of described write transistor is reduced while beginning.

[supplementary notes 6]

According to any one the described image element circuit in supplementary notes 1 to 5,

Wherein said write transistor has the Characteristics Control terminal that can control threshold voltage, and

Characteristics Control part is for being applied to described Characteristics Control by the control signal controlling described threshold voltage Terminal.

[supplementary notes 7]

According to the image element circuit described in supplementary notes 6,

Wherein said write transistor is metal-oxide membranous type field-effect transistor.

[supplementary notes 8]

According to the image element circuit described in supplementary notes 6,

Wherein said write transistor is back of the body gate type thin film transistor.

[supplementary notes 9]

According to any one the described image element circuit in supplementary notes 6 to 8,

Wherein electric capacity unit is set between the Characteristics Control terminal and control electrode terminal of described write transistor Part, the control applying the conduction/non-conduction for controlling described write transistor to described control electrode terminal is believed Number.

[supplementary notes 10]

Wherein electricity is set at described Characteristics Control terminal with between the video signal cable transmitting video signal Hold element.

[supplementary notes 11]

According to the image element circuit described in supplementary notes 10, also include:

Time constant adjustment member, it is constructed by the adjustment of described capacity cell and is applied to described characteristic control The time constant of the signal of terminal processed.

[supplementary notes 12]

According to the image element circuit described in supplementary notes 11,

Wherein said time constant adjustment member has the resistive element being connected to described Characteristics Control terminal.

[supplementary notes 13]

Wherein the pulse corresponding to the control signal of the conduction/non-conduction for controlling described write transistor is believed Number it is applied to described Characteristics Control terminal.

[supplementary notes 14]

According to supplementary notes 13 described in image element circuit, also include following at least one:

Pulse width adjustment member, it is configured to adjust for the conduction/non-conduction controlling described write transistor The pulse width of control signal, and described control signal is applied to described Characteristics Control terminal, institute State pulse width to be arranged in conducting state by described write transistor；And

Amplitude adjustment member, its amplitude being configured to adjust the signal being applied to described Characteristics Control terminal.

[supplementary notes 15]

According to any one the described image element circuit in supplementary notes 1 to 14, also include:

Pixel portion, arranges display element in described pixel portion,

The characteristic of the write transistor during wherein Characteristics Control part controls each display element.

[supplementary notes 16]

According to the image element circuit described in supplementary notes 15,

Wherein said pixel portion has the described display element arranged with two-dimensional matrix form.

[supplementary notes 17]

According to any one the described image element circuit in supplementary notes 1 to 16,

Wherein display element is emissive type.

[supplementary notes 18]

A kind of display device, including:

Multiple image element circuits, described image element circuit includes display part, storage capacitor, would correspond to regard Frequently the driving voltage of signal writes the write transistor of described storage capacitor and for described based on writing The driving voltage of storage capacitor drives the driving transistor of described display part, and described image element circuit is by cloth Put；And

[supplementary notes 19]

A kind of electronic installation, including:

Multiple image element circuits, described image element circuit includes display part, stores capacitor, for by correspondence Driving voltage in video signal writes the write transistor of described storage capacitor and for based on writing The driving voltage of described storage capacitor drives the driving transistor of described display part, described image element circuit It is arranged；

Signal generator divides, for producing the video signal being applied to described write transistor；And

[supplementary notes 20]

A kind of pixel circuit drive method driving image element circuit, described image element circuit includes for by correspondence Driving voltage in video signal writes the write transistor of storage capacitor and for driving display part Driving transistor, described driving method includes:

To write the process operation of described storage capacitor with the driving voltage that would correspond to described video signal The mode of association, controls the characteristic of described write transistor.

The disclosure comprises the Japanese earlier patent application relating on June 8th, 2011 and submitting in Japan Office Theme disclosed in JP 2011-128238, is herein incorporated entire contents by quoting.

Claims

1. an image element circuit, including:

Light-emitting component；

Storage capacitor；

Drive transistor, be used for, based on the driving voltage writing described storage capacitor, driving described luminescence Element,

The characteristic of wherein said write transistor can by with the driving voltage that would correspond to described video signal The mode processing operation association writing described storage capacitor controls,

Described write transistor has the Characteristics Control terminal that can control threshold voltage,

Characteristics Control part is for being applied to described Characteristics Control by the control signal controlling described threshold voltage Terminal, and

Between the Characteristics Control terminal and control electrode terminal of described write transistor, capacity cell is set, to Described control electrode terminal applies the control signal of the conduction/non-conduction for controlling described write transistor.

Image element circuit the most according to claim 1, also includes:

Image element circuit the most according to claim 2,

4. according to the image element circuit described in any one in claim 1-3, wherein:

Described Characteristics Control part is configured to write institute with the driving voltage that would correspond to described video signal State the mode processing operation association of storage capacitor, control the characteristic of described write transistor.

5. according to the image element circuit described in any one in claim 1-3,

Image element circuit the most according to claim 5,

8. according to the image element circuit described in any one in claim 1-3,

9. according to the image element circuit described in any one in claim 1-3,

10., according to the image element circuit described in any one in claim 1-3, also include:

Pixel portion, arranges light-emitting component in described pixel portion,

The characteristic of the write transistor during wherein Characteristics Control part controls each light-emitting component.

11. image element circuits according to claim 10,

Wherein said pixel portion has the described light-emitting component arranged with two-dimensional matrix form.

12. 1 kinds of image element circuits, including:

Light-emitting component；

Storage capacitor；

At described Characteristics Control terminal with between the video signal cable transmitting described video signal, electricity is set Hold element.

13. image element circuits according to claim 12, wherein:

14. image element circuits according to claim 12,

15. image element circuits according to claim 14,

16. image element circuits according to claim 14,

17. image element circuits according to claim 12,

18. image element circuits according to claim 12,

19. image element circuits according to claim 12, also include:

Pixel portion, arranges light-emitting component in described pixel portion,

20. image element circuits according to claim 19,

21. 1 kinds of image element circuits, including:

Light-emitting component；

Storage capacitor；

Pulse signal quilt corresponding to the control signal of the conduction/non-conduction for controlling described write transistor It is applied to described Characteristics Control terminal.

22. image element circuits according to claim 21, also include following at least one:

Pulse width adjustment member, it is configured to adjust for the conduction/non-conduction controlling described write transistor The pulse width of control signal, and by the described conduction/non-conduction being used for controlling described write transistor Control signal is applied to described Characteristics Control terminal, and described write transistor is arranged on and leads by described pulse width In logical state；And

23. image element circuits according to claim 21, wherein:

24. image element circuits according to claim 21,

25. image element circuits according to claim 24,

26. image element circuits according to claim 24,

27. image element circuits according to claim 21,

28. image element circuits according to claim 21,

29. image element circuits according to claim 21, also include:

Pixel portion, arranges light-emitting component in described pixel portion,

30. image element circuits according to claim 29,

31. 1 kinds of display devices, including:

Multiple image element circuits, described image element circuit includes light-emitting component, storage capacitor, would correspond to regard Frequently the driving voltage of signal writes the write transistor of described storage capacitor and for described based on writing The driving voltage of storage capacitor drives the driving transistor of described light-emitting component, and described image element circuit is by cloth Put；And

Characteristics Control part, it is configured to write institute with the driving voltage that would correspond to described video signal State the mode processing operation association of storage capacitor, control the characteristic of described write transistor,

Wherein said write transistor has the Characteristics Control terminal that can control threshold voltage,

The control signal controlling described threshold voltage is applied to described Characteristics Control by described Characteristics Control part Terminal, and

32. 1 kinds of display devices, including:

33. 1 kinds of display devices, including:

34. 1 kinds of display devices, including:

Multiple image element circuits；

Multiple holding wires；And

Multiple scan lines,

Wherein said image element circuit includes light-emitting component, storage capacitor, write transistor and drives crystal Pipe,

According to the control signal from scan line, described write transistor is arranged in conducting state, and institute State write transistor and the video signal from holding wire is applied to described storage capacitor；

Described storage capacitor keeps the driving voltage of the video signal corresponding to being applied；

Based on described driving voltage, drive described driving transistor, in order to be fed through described light-emitting component Electric current,

Described write transistor includes backgate terminal and gate terminal, and

Capacity cell and resistive element is connected between described backgate terminal and described gate terminal.

35. 1 kinds of electronic installations, including:

Multiple image element circuits, described image element circuit includes light-emitting component, stores capacitor, for by correspondence Driving voltage in video signal writes the write transistor of described storage capacitor and for based on writing The driving voltage of described storage capacitor drives the driving transistor of described light-emitting component, described image element circuit It is arranged；

36. 1 kinds of electronic installations, including:

37. 1 kinds of electronic installations, including:

The image element circuit of 38. 1 kinds of image element circuits driven as according to any one of claim 1-30 drives Method, described image element circuit includes writing storage capacitor for the driving voltage that would correspond to video signal Write transistor and for driving the driving transistor of display part, described driving method includes: